Bridging the gap: examining circadian biology and fatigue alongside work schedules

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Plano, Giannina Bellone, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4345165/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract The socio-cultural, industrial, and business demands of our current society require us to be active 24 hours a day, 7 days a week. This phenomenon implies working conditions that lead employees to perform their tasks in rotating shifts, during nighttime hours, and for extended shifts, thereby disrupting their biological rhythms, most fundamentally their sleep patterns. There is a need for naturalistic studies to evaluate the relationship between the specific design of work shifts and the actual amount of achievedsleep. To achieve this goal, we conducted a comprehensive study involving employees of the logistic chain of an oil company in Argentina. We compared three different types of work schedules that encompassed extended and rotating shifts work: 1) one in which workers completed two days of 12 h of daytime shifts followed by two consecutive 12 h night shifts, followed by four work-free days(“2x2x4x4x4” schedule), 2) one in which workers alternated four consecutive 12 h daytime shifts and four consecutive 12 h night shifts, flanked by four work-free days (“4x4x4” schedule), 3) and another, non-rotating, schedule involving continuous 12 h daytime shifts during 40 days, with no work-free days in between (“fixed 12h” schedule). Our study employed objective measurements such as wrist-actigraphy to record sleep patterns, temperature loggers to monitor peripheral temperature rhythms, as well as subjective self-reports regarding fatigue, somnolence, and psycho-affective features. In all cases, the duration of sleep during the resting period was significantly less than the recommended 7 hours of nocturnal sleep. The “2x2x4”schedule resulted in decreased sleep regularity and increased circadian disruption, associated with more nocturnal sleep time after diurnal work. Also, this shift exhibited higher levels of insomnia, increased fatigue impact, lower alertness levels, and heightened symptoms of depression. Our findings indicate that specific parameters vary depending on the type of schedule worked suggesting that, in practical terms, certain schedules are healthier and safer for these workers. These results provide valuable insights for the design of safer and healthier work schedules, with the potential to enhance worker well-being and overall productivity. Biological sciences/Neuroscience/Circadian rhythms and sleep/Circadian regulation Biological sciences/Neuroscience/Circadian rhythms and sleep/Sleep deprivation shiftwork fatigue working schedules sleep Figures Figure 1 Figure 2 Figure 3 INTRODUCTION The introduction of artificial electric lighting in the 19th century and the restructuring of working times has progressively led to a departure from our usual 24-hour cycles, which respond to the alternating light-dark environment. Society is increasingly dependent on 24-hour, seven-days-a-week operations (the so-called "24/7 society") that necessarily require either or both night- or rotating-shifts work. Many industries and services rely on a continuous workforce, including energy production, product manufacturing, transportation, health care, and law enforcement. 1 In addition to the adverse effects of long working hours, exposure to nighttime light, and psychosocial factors, the health consequences of shiftwork must first be understood in terms of a fundamental desynchronization between the circadian rhythm of the endogenous biological clock and external synchronizers, the primary one being sunlight. The short-term consequences of shiftwork and nocturnal work are related to an increase in errors at home or in the workplace, leading to an increased risk of incidents and accidents. Some studies conducted in organizations in the United States, France, and the United Kingdom show that the number of workplace accidents related to sleep-related problems can vary from 10–30% of the total. 2 Furthermore, it has been shown that 17 h of continuous wakefulness has the same effect on the level of reaction as having a blood alcohol level above 0.5 g/l, the legal limit for non-professional drivers in many countries. 3 In the long term, it increases the risk of suffering from various chronic, complex and multifactorial diseases, including cardiovascular, metabolic, neurodegenerative, oncological, immune and mental pathologies, among others. 4 It has been estimated that approximately 20% of the workforce in industrialized countries is employed in a job requiring rotating shifts work. Although the actual prevalence of clinically significant sleep disorders and excessive daytime sleepiness is unknown, it is estimated to affect between 2–5% of the general population. The prevalence of shiftwork disorder among rotating and night shift workers has been estimated to be between 10% and 38%. However, these figures do not include early morning or split-shift workers, who may be considered as at-risk groups as well . 5 Companies working in the energy sector must operate continuously 24 hours a day, 365 days a year, leading workers to the development of fatigue, a complex state characterized by decreased attention and reduced mental and physical performance, and often accompanied by drowsiness, which can frequently trigger incidents and/or accidents. 6 There is a need for studies in naturalistic settings to address how to improve the organization of night and shift schedules. 7 We obtained data from workers in a naturalistic environment, with the objective of evaluating the relationship between the specific design of work shifts and the actual amount of sleep achieved. Our analysis provides valuable insights for the design of safer and healthier work schedules, with the potential to enhance worker well-being and overall productivity. MATERIALS AND METHODS Study design and population This was an observational, analytical, and cross-sectional exploratory study conducted between March 2021 and September 2023. It was conducted in a sample of 44 male shift-workers from an oil company in Argentina, who performed their work in three different schedules, which are detailed in Fig. 1 . The three work schedules differ in the distribution of 12-hour extended work shifts and free days: in the “2x2x4” schedule, workers completed two days of 12 h of daytime shifts followed by two consecutive 12 h night shifts, followed by four work-free days; in the “4x4x4” schedule, workers alternated four consecutive 12 h daytime shifts and four consecutive 12 h night shifts, flanked by four work-free days; and in the “fixed 12h” schedule, workers had continuous diurnal work shifts during 40 days (without rest days), associated with the periods in which the plants were shutdown for maintenance. Measurements Questionnaires Questionnaires were completed by participants on an online platform developed for this study. Demographic data, and work, fatigue, alertness and performance characteristics were collected. Overweight was defined as BMI ≥ 25, and obesity as BMI ≥ 30. Participants reported the distance to work from their homes, whether they had a secondary job, the number of days in which they experienced significant tiredness in the last month, the impact of fatigue in their usual activities in the last year, and their levels of alertness during their work tasks in the last month. They also were asked about coffee and mate consumption. Mate is a traditional South American caffeinated beverage made from steeping dried leaves of the yerba mate plant in hot water. Insomnia was evaluated through the Insomnia Severity Index (ISI). It consists of seven items that inquire about the severity of sleep onset, sleep maintenance, early morning awakenings, sleep dissatisfaction, interference with daily functioning, noticeability of impairment attributed to sleep difficulties, and distress caused by sleep problems. Each item is rated on a scale from 0 to 4, with higher scores indicating greater severity. The total score ranges from 0 to 28, with higher scores indicating more severe insomnia. Scores are interpreted as follows: no insomnia (0–7); sub-threshold insomnia ( 8 – 14 ); moderate insomnia ( 15 – 21 ); and severe insomnia ( 22 – 28 ). 8 Sleep apnea was assessed using the STOP-BANG index. It comprises eight yes-or-no questions, targeting the following risk factors associated with sleep apnea: tiredness, observed apnea, high blood pressure, elevated BMI, age, neck circumference, and gender. The total score ranges from 0 to 8, with a low risk indicated by scores of 0–2, intermediate risk by scores of 3–4, and high risk by scores of 5 or higher. 9 The Spanish validated version of the Epworth Sleepiness Scale (ESS) was used to measure daytime somnolence. An ESS score between 11 and 14 indicates mild daytime sleepiness, a score between 15 and 17 indicates moderate daytime sleepiness, while a score higher than 18 indicates excessive daytime sleepiness symptoms. 10 Psycho-affective variables were studied using Spanish validated versions of the Beck Anxiety Inventory (BAI), and the Beck Depression Inventory-II (BDI-II). The BAI is a screening measure of frequency and intensity of anxiety symptoms that contains 21 items on a 4-point Likert scale, with 0 representing 'not at all' and 3 being 'severely'. Scores of 0–7 are considered “minimal anxiety”; 8–15 are “mild anxiety”; 16–25 are “moderate anxiety”; and 26–63 are “severe anxiety”. 11 The BDI-II 12 is a widely used self-report questionnaire to evaluate depression symptoms, that contains 21 items with a 4-point Likert scale ranging from 0 (not at all) to 3 (severely). The inventory classifies symptom severity in four categories: minimal (0–13 pts), mild (14–19 pts), moderate (20–28 pts) or severe (29–63 pts) depression. 13 Sleep-wake cycle The sleep-wake cycle was studied using the ActTrust wrist accelerometers (Condor Instruments, Sao Paulo, Brazil). Participants were asked to wear the devices in the nondominant wrist and to complete sleep logs during at least 15 consecutive days. Sleep logs helped us to visually identify “in bed” episodes in actigraphic recordings. Actigraphy data was analyzed using ActStudio software (Condor Instruments, Sao Paulo, Brazil). The first sleep period after a nocturnal working day was considered as the main sleep period of that day. Other sleep periods starting between 8AM and 7PM and ending before 9PM were considered as naps. The following variables were reported: mean nocturnal sleep between diurnal workdays, mean diurnal sleep after nocturnal workdays, mean nocturnal sleep on free-days, mean total nap duration and mean duration of naps between nocturnal shifts. Midtime of sleep during free days was computed as a proxy for estimating workers' chronotype. 14,15 For this calculation, we exclusively utilized sleep data from the final two days of the free period since we assume that at that point the sleep debt has already been recovered. Additionally, we computed midsleep times for the nights between diurnal workdays using data from all three nights in between working shifts. As the “fixed 12-hour” schedule did not have free days during the studied period, the midtime of sleep was only calculated for the other two schedules. The sleep regularity index (SRI) was calculated through the formula described by Philips et al. SRI was only calculated for participants with at least eight complete consecutive days of sleep recordings. 16,17 The index represents a measure of the probability (not the probability itself) of a participant being in the same sleep or wake state at two time-points 24 h apart, and can take values that vary from − 100 to 100: a person who falls asleep and wakes up precisely at the same times every day will have an SRI of 100; a person who can be asleep or awake randomly throughout days will score 0; finally, in an infrequent albeit possible scenario for our participants, continuous periods of wakefulness (or, theoretically, of sleep as well) of over 24 hours could generate negative SRI values. 17 Temperature circadian rhythm The wrist temperature signal was acquired using the Condor actigraphic devices, with sampling conducted every minute. Values below 25°C were considered as NA. A maximum of 20% missing values and 6-hour contiguous missing values were tolerated. Missing values were substituted using linear interpolation. A 60-minute filter was then applied to the dataset. Finally, a cosinor model featuring a 24-hour main rhythm and a 12-hour harmonic was applied to the data. We reported the amplitude of each rhythm and the rhythm strength (percentage of the total variance explained by the model). 18,19 Data analysis Numerical variables in the descriptive analysis are shown as mean ± standard deviation (SD), and categorical variables as percentage and frequencies (%). For categorical values, differences between groups were assessed using chi-square. For numerical variables, with exception of midtime of sleep during free days, differences between groups were compared by means of a one-way ANOVA followed by a Tukey post-hoc test. For midtime of sleep during free days, differences between “2x2x4” and “4x4x4” schedules were assessed using an independent samples t-test. Finally, for “2x2x4” and “4x4x4” schedules we used a mixed-effects linear model to evaluate sleep variations within and between schedules, including sleep duration or midsleep as dependent variables, subject as a random factor and schedule, time of day and type of day as fixed factors. Ethical aspects All subjects received detailed information about the procedures and gave written informed consent to participate before the study. The study was performed in accordance with the Declaration of Helsinki and its amendments and was approved by the review board of the Universidad Nacional de Quilmes. RESULTS Sociodemographic characteristics Sociodemographic characteristics and habits are shown in Table 1 . The sample consisted of 44 male shift-workers: 18 under the “2x2x4” scheme, 15 under the “4x4x4” scheme and 11 under the “fixed 12h” scheme (Fig. 1 ). Groups did not differ significantly in age, the frequency of overweight, obesity, physical activity, or caffeinated drinks consumption. Table 1 Workers sociodemographic characteristics and habits according to the schedule worked Variable “2x2x4” schedule “4x4x4 schedule” “fixed 12h” schedule p Valid n Mean/n SD/% Valid n Mean/n SD/% Valid n Mean/n SD/% Mean age (yr) 17 38 9 15 43 8 11 43 7 0.265 Body mass index (kg/m 2 ) 16 28.3 5.9 15 29.5 3.2 11 27.0 2.9 0.385 Weight (%): Normal 16 6 47 15 2 13 11 3 27 0.463 Overweight 16 7 44 15 7 47 11 6 55 Obesity 16 3 19 15 6 40 11 2 18 Physical activity (%): 0.098 Less than 2 hours per week 15 4 27 15 7 47 11 9 82 2 to 4 hours per week 15 4 27 15 3 20 11 1 9 More than 4 hours per week 15 7 47 15 5 33 11 1 9 Coffee consumption (%): 0.640 No consumption 16 8 50 15 6 40 11 7 64 Sporadically 16 4 25 15 6 40 11 1 9 Once a day 16 3 19 15 3 20 11 2 18 Twice a day 16 1 6 15 0 0 11 1 9 Three or more times per day 16 0 0 15 0 0 11 0 0 Mate consumption (%): No consumption 16 1 6 15 1 7 11 2 18 0.624 Sporadically 16 1 6 15 1 7 11 0 0 Once a day 16 1 6 15 0 0 11 1 9 Twice a day 16 8 50 15 5 33 11 6 55 Three or more times per day 16 5 31 15 8 53 11 2 18 Commute time to work (min) 17 24 22 15 61 ( 1 ) 14 11 26 9 < 0.001 Side job (%) 17 1 6 15 6 40 11 0 0 0.008 Shown are mean (SD) or n (%). Differences were assessed through one-way ANOVA followed by Tukey post-hoc test for numerical variables or chi-square for categorical ones. ( 1 ) Different from the others. Workers under “4x4x4” schedule had longer commute times compared to workers under “2x2x4” and “fixed 12h” schedules (p < 0.001; post-hoc test: p < 0.001 for “4x4x4” schedule vs. “2x2x4” schedule and p < 0.001 for “4x4x4” schedule vs. “fixed 12h” schedule). Additionally, a higher percentage of workers on “4x4x4” schedule reported holding a secondary job (p = 0.008) (Table 1 ). Sleep characteristics Sleep characteristics of the participants are presented in Table 2 . The mean duration of nocturnal sleep on workdays was 5h:42m for workers under the “2x2x4” schedule, 5h:10m for those under the “4x4x4” schedule, and 6h:19m for those under the “fixed 12h” schedule. Nocturnal sleep for workers under the “4x4x4” schedule was more than an hour shorter than for workers under the “fixed 12h” schedule (p = 0.003, post-hoc test: p = 0.002) (Table 2 ). Table 2 Workers sleep characteristics Variable “2x2x4” schedule “4x4x4 schedule” “fixed 12h” schedule p Valid n Mean/n SD/% Valid n Mean/n SD/% Valid n Mean/n SD/% Mean nocturnal sleep duration between diurnal workdays (hh:mm) 18 05:42 00:46 15 05:10 ( 1 ) 00:53 11 06:19 00:38 0.003 Mean diurnal sleep duration after nocturnal workdays (hh:mm) 18 03:53 00:53 15 03:26 01:17 N/A N/A N/A 0.257 Mean nocturnal sleep duration on free-days (hh:mm) 18 08:03 00:55 15 07:27 00:43 N/A N/A N/A 0.041 Mean total nap duration (hh:mm) 13 01:39 00:32 11 01:28 00:21 N/A N/A N/A 0.371 Mean duration of naps between nocturnal shifts (hh:mm) 13 01:44 00:37 10 01:32 00:21 N/A N/A N/A 0.339 Midsleep between diurnal workdays (hh:mm) 18 02:43 00:40 15 02:28 ( 1 ) 00:33 11 02:52 00:42 0.001 Midsleep after nocturnal workdays (hh:mm) 18 10:52 01:42 15 10:47 01:26 N/A N/A N/A 0.766 Midsleep on free-days (hh:mm) 18 05:22 02:09 15 04:50 01:30 N/A N/A N/A 0.197 Sleep regularity index 16 39 ( 2 ) 7 15 54 ( 2 ) 7 11 72 ( 2 ) 8 < 0.001 Sleepiness (ESS) 17 6.6 4.4 15 5.1 3.0 11 7 5.0 0.466 Insomnia (ISI) 17 6.2 5.2 15 2.2 ( 3 ) 1.7 11 6.1 4.4 0.017 Apnea (STOP BANG, %) 0.873 High risk 17 2 12 14 2 14 11 2 18 Intermediate risk 17 3 18 14 2 14 11 1 9 Low risk 17 12 71 14 10 71 11 8 73 Shown are mean (SD) or n (%). Differences were assessed through one-way ANOVA followed by Tukey post-hoc test for numerical variables or chi-square test for categorical ones. ( 1 ) Different from “fixed 12h”. ( 2 ) Different between each other. ( 3 ) Different from “2x2x4”. ESS: Epworth sleepiness scale. ISI: Insomnia severity index. We did not find differences in diurnal sleep after nocturnal shifts between participants under the “2x2x4” and the “4x4x4” schedules (“fixed 12h” schedule does not include nocturnal workdays). Regarding sleep during free days, workers under the “4x4x4” schedule slept 30 minutes less than those under the “2x2x4” schedule (p = 0.041). We found that 73% of workers in the “2x2x4” schedule and 67% under the “4x4x4” schedule took naps before and between nocturnal workdays (p = ns ), and we did not find differences in nap duration between schedules (Table 2 ). Nocturnal sleep midsleep times on free days was similar between “2x2x4” and “4x4x4” schedules. On workdays, 2x2x4 midsleep for “4x4x4” schedule was significantly earlier than for “fixed 12h” schedule (p < 0.001). Regarding sleep regularity, we determined a significantly lower SRI for workers under the “2x2x4” schedule compared to “4x4x4” and “fixed 12h“ schedules, and for workers under the “4x4x4” schedule compared to the “fixed 12h” schedule (p < 0.001, post-hoc test: p < 0.001 for all contrasts) (Table 2 ). Figure 2 A shows sleep duration across the “2x2x4” and “4x4x4” schedules. Sleep duration during the day after nocturnal work shifts was significantly shorter than sleep during the night between diurnal shifts for both schedules (Fig. 2 B, "time of day" effect: p < 0.001). Also, midsleep was earlier on diurnal working days compared to free days for both schedules (Fig. 2 C, "type of day" effect: p < 0.001). Finally, we did not find differences in diurnal sleepiness or sleep apnea risk between the schedules. However, workers under the “2x2x4” schedule showed higher scores on the Insomnia Severity Index than those under the “4x4x4” one (p = 0.017, post-hoc test: p = 0.024) (Table 2 ). Temperature circadian rhythm Table 3 shows the results of the circadian temperature rhythm analysis. Sample sizes decreased for all groups due to the acceptance criteria for maximum NA values, which did not significantly differ between groups. Significant differences were observed for the 12-hour amplitude of the temperature rhythm and the percentage of variance explained by the model. The “2x2x4” schedule differed from the “fixed 12h” schedule, while the “4x4x4” schedule presented intermediate values between both (Table 3 ). Table 3 Circadian temperature rhythm analysis “2x2x4” schedule (n = 10) “4x4x4” schedule (n = 11) “fixed 12 h” schedule (n = 8) p Mean SD Mean SD Mean SD Record length (hr) 324 44 357 50 320 28 0.115 % NA 3.1 3.2 5.0 4.6 1.7 1.7 0.148 Max. cont. NA (min) 123 108 150 93 87 107 0.420 Amp 24 hr (°C) 0.8 0.3 1.0 0.7 1.1 0.6 0.258 Amp 12 hr (°C) 0.5 0.3 0.7 0.3 1.0 0.6 0.030 ( 1 ) Rhythm strength (%) 14.1 5.4 22.4 9.9 34.1 18.1 0.005 ( 1 ) Shown are mean (SD). One-way ANOVA followed by Tukey post-hoc test. Max. cont. NA: maximum contiguous NA values; rhythm strength: percent of the variance explained by the model. ( 1 ) “fixed 12 h” differs from “2x2x4”. Fatigue impact, alertness and wellbeing Fatigue impact, alertness and wellbeing are presented in Table 4 . Workers under the “fixed 12h” schedule reported a higher number of days with significant tiredness in the last month compared to those under the “4x4x4” schedule (p = 0.022, post-hoc test: p = 0.019). Workers under the “4x4x4” schedule reported being less negatively impacted by fatigue in their ability to learn new tasks (p = 0.009) and overall job satisfaction (p = 0.009) compared to workers under the “2x2x4” and “fixed 12h” schedules; and in their relationships with coworkers (p = 0.017) compared to workers under the “fixed 12h” schedule (Table 4 ). Table 4 Reported fatigue and its impact on shiftworkers performance. relationships and wellbeing “2x2x4” schedule “4x4x4 schedule” “fixed 12h” schedule p Variable Valid n Mean/n SD/% Valid n Mean/n SD/% Valid n Mean/n SD/% Reported fatigue negative impact on… … performance at work 0.085 Never 16 3 19 14 4 29 11 2 18 Rarely 16 6 38 14 7 50 11 4 36 Sometimes 16 5 31 14 3 21 11 4 36 Frequently 16 2 13 14 0 0 11 1 9 … learning new tasks 0.009 Never 17 6 35 15 13 87 11 3 27 Rarely 17 8 47 15 0 0 11 5 46 Sometimes 17 3 18 15 2 13 11 3 27 Frequently 17 0 0 15 0 0 11 0 0 … their overall employee satisfaction 0.009 Never 17 5 29 15 14 93 11 4 36 Rarely 17 5 29 15 1 7 11 2 18 Sometimes 17 6 35 15 0 0 11 3 27 Frequently 17 1 6 15 0 0 11 2 18 … their co-workers safety 0.332 Never 17 5 29 15 14 93 11 4 36 Rarely 17 5 29 15 1 7 11 2 18 Sometimes 17 6 35 15 0 0 11 3 27 Frequently 17 0 0 15 0 0 11 0 0 … their own safety 0.314 Never 17 13 77 15 14 93 11 8 73 Rarely 17 4 24 15 1 7 11 2 18 Sometimes 17 0 0 15 0 0 11 1 9 Frequently 17 0 0 15 0 0 11 0 0 … the relationship with co-workers 0.017 Never 17 13 77 15 14 93 11 8 73 Rarely 17 4 24 15 1 7 11 2 18 Sometimes 17 0 0 15 0 0 11 1 9 Frequently 17 0 0 15 0 0 11 0 0 Reported level of alertness to carry out their work task in the … … middle of the day 0.169 Not at all rested and alert 17 0 0 15 0 0 11 1 9 Poorly rested and alert 17 1 6 15 0 0 11 1 9 Somewhat rested and alert 17 5 29 15 1 7 11 3 27 Fairly rested and alert 17 6 35 15 5 33 11 5 46 Very rested and alert 17 5 29 15 9 60 11 1 9 … middle of the night 0.028 Not at all rested and alert 17 0 0 15 0 0 N/A N/A N/A Poorly rested and alert 17 5 29 15 0 0 N/A N/A N/A Somewhat rested and alert 17 5 29 15 2 13 N/A N/A N/A Fairly rested and alert 17 5 29 15 6 40 N/A N/A N/A Very rested and alert 17 2 12 15 7 47 N/A N/A N/A Significant tiredness (# days) 13 6 6 14 2 ( 1 ) 3 10 8 8 0.022 Anxiety (BAI score) 17 2.7 3.7 15 1.7 2.4 11 4.6 3.6 0.095 Depression (BDI II score) 17 4.4 3.8 15 0.9 ( 2 ) 2.1 11 5.8 5.4 0.005 Shown are mean (SD) or n (%). Differences were assessed through one-way ANOVA followed by Tukey post-hoc test for numerical variables or chi-square test for categorical ones. ( 1 ) Different from “12 h fixed”; ( 2 ) Different from the others. We did not find differences between schedules in the reported levels of alertness in the middle of diurnal workdays, but workers under the “2x2x4” schedule reported lower levels of alertness in the middle of nocturnal work shifts compared to those under the “4x4x4” schedule (p = 0.028) (Table 4 ). Finally, we noted higher scores for depression symptoms for workers under the “2x2x4” and “fixed 12h” schedules compared to those under the “4x4x4” schedule (p = 0.005), while anxiety levels were similar (Table 4 ). DISCUSSION The scheduling of shiftwork depends on several factors, including productivity, costs, and workers’ wellbeing. Indeed, shiftwork has emerged as one of the key translational opportunities for circadian research, together with a chronobiological approach to health issues. Among the different variables that can be optimized is the number of days under nocturnal or diurnal tasks and the rest periods between them. This is a complex issue that should take into account several variables, balancing productivity, presenteeism, accident and incident rates, health and the impact on the social life of workers. 1 Since there is a clear link between shift duration, sleep, and health outcomes, 20 and the effects of continuous sleep deprivation and irregularity is cumulative, 21 a correct decision in terms of the schedule might have long-lasting consequences. Indeed, many other variables contribute to both productivity and wellbeing during shiftwork, including environmental factors (i.e., illumination, feeding schedules, etc.), individual characteristics such as chronotype and even commuting time and distance, and the nature of the work being performed, as well as stress and inherent working hazards. Since shiftwork also affects mood vulnerability, 18,22 it is not surprising that such routine impacts both co-workers and their family relationships. Here we examined the effect of three different working schedules on the sleep-wake performance of workers in the logistics branch of one of the biggest oil companies in South America. In all cases, the duration of sleep during the resting period was significantly less than the recommended 7 hours of nocturnal sleep. 23 The “2x2x4” schedule showed increased nocturnal sleep time after diurnal work, decreased sleep regularity and a dampened circadian temperature rhythm. Additionally, this shift exhibited higher levels of insomnia, increased fatigue impact, lower alertness levels, and heightened symptoms of depression (Fig. 3 ). Participants in our study only worked 12-h shifts. There is much discussion regarding their advantage over 8-h shifts; including an increased sleep opportunity during rest days. However, some reports state that this schedule might decrease alertness 24 and deteriorate domestic life. 25 While there is a clear consensus in the fact that any shiftwork schedule will result in circadian and sleep disruption, especially at the extremes of very long or very short types of rotation, there is no clear effect of switching between 8- and 12-h shifts. 26 Since oil industry must rely on 24/7 activities, the most usual schedule in companies around the world involves 12-h shifts for 2 or 4 consecutive days (in contrast to the previously implemented 8-h shifts system, with less frequent rotation). However, long work hours are associated with short sleep duration, sleep disruption, and decreased alertness. 24,27,28 The impact of shiftwork schedules in the oil industry on the domestic and social life of workers has also been highlighted elsewhere. 29 The disruption of sleep patterns and circadian temperature rhythms observed in workers under the "2x2x4" scheme may probably be attributed to the shorter duration of shifts. Sleep regularity, a measure of the consistency of day-to-day variability in sleep–wake timing – has recently received much attention, in terms of its importance for health, safety and productivity). It is known that fluctuations in both environmental and behavioral factors associated with variability in sleep timing can induce circadian disruption 30 and, in turn, sleep disturbances. 4 In this regard, the increased sleep duration observed in this group could be explained as a compensatory mechanism for the disruption of circadian rhythms. While extending sleep on non-work days is a common human pattern to counter sleep deficiency on work days, 30 this practice may not be sufficient in the 2x4 schedule, resulting in additional sleep during work days. Indeed, in a previous study involving long-haul bus drivers working with a two-up operations system, we reported that workers under high fatigue risk working schedules showed increased sleep duration during the trips on the bus. 19 The results obtained from the circadian analysis of temperature reinforce what has been discussed so far. The "2x2x4" schedule exhibited lower circadian robustness compared to the "fixed 12-hour” schedule, while the "4x4x4" schedule showed intermediate values, without significantly differentiating from the other groups. Taken together, this reveals a greater circadian disruption in the "2x2x4" schedule compared to the "4x4x4" one. These results are also consistent with the disruption of the expression of the circadian rhythm of wrist temperature by shift-work reported by our group in drivers exposed to high-risk working schedules 19 and by others. 31–33 In our work, we observed that workers from “2x2x4” the schedule reported a higher number of days with significant tiredness in the last month, a greater negative impact of fatigue on their daily activities, and more depression symptoms. Also, these workers reported lower levels of alertness in the middle of night shifts than workers from the “4x4x4” schedule. This aligns with the circadian disruption observed in this group, known to potentially result in sleep disturbances, sleep medication consumption, persistent fatigue and mood disorders, and/or burn out, which could compromise safety and health. 4 In fact, a report from the 1990s 34 investigated oil refinery workers during their night shift, finding significant changes in endocrine rhythms, with a lower amplitude for cortisol and higher peaks for melatonin. It is also well-known that the number of years spent on shiftwork in this industry further affects sleep, health, and productivity. 35,36 More recently, studies have demonstrated that impaired sleep quality and shorter sleep duration in oil activity shift workers are associated with increased fatigue-related incidents. 6 We also considered chronotype, which might affect the outcome of shift workers, with certain advantages for late-types. 37 In our case, we did not find significant differences in midsleep on free days between Schedules “2x2x4” and “4x4x4”. The midpoint of sleep on free days for “2x2x4” schedule was at 05:22 am, while for “4x4x4” schedule it was at 04:50 am, both corresponding to slightly late chronotypes; 38 however, it should be noted that the Argentinian is a particularly late culture. Since the alignment of individual chronotype with working hours might reduce circadian disruption, 39 more data is needed to assess the impact of this variable on performance and wellness in this particular industry. According to the guiding principles of the American Academy of Sleep Medicine and the Sleep Research Society (2021), 40 the duration of working shifts is linked to adverse performance, safety, and health outcomes, and several countermeasures are proposed to overcome such adverse consequences. The first of these measures is to “schedule interventions to maximize daily sleep opportunity, consistently align work with the biological drive for wakefulness and increase time for recovery after extended duties or multiple shifts.” Here we have compared three different shiftwork schedules for the oil industry, finding that a “2x2x4” shift work schedule showed decreased sleep regularity and a dampened circadian temperature rhythm, associated with higher levels of insomnia, increased fatigue impact, lower alertness levels, and heightened symptoms of depression. There are several confounding factors that should be considered, and were not addressed here, to fully understand the impact of shift work design on sleep, alertness and fatigue. Among these are the nature of tasks performed, the environmental conditions both at work and at home, and the types of jobs. However, we believe that our results contribute to a further understanding of the optimal working conditions that our 24/7 society demands to achieve improved outcomes in health, wellness, and productivity, representing a clear case for translational circadian research. Declarations Author Contribution MMF, LC, SAP and GB performed the field recordings and surveys. MMF, LC, DAG and DEG wrote the main manuscript text and prepared the figures and tables. All authors reviewed the manuscript. ACKNOWLEDGEMENTS We are very grateful to the workers and management of YPF, the national oil company, for participating in this study and providing help and advice with the design of the project. This work was partially financed by a grant from Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), PICT 2020–02452. MMF, LPG, SAP, DEV and DAG are members of the National Research Council (CONICET). Data Availability Data is provided within the manuscript. Raw data will be provided upon reasonable request. References James, S. M., Honn, K. A., Gaddameedhi, S. & Van Dongen, H. P. A. Shift Work: Disrupted Circadian Rhythms and Sleep—Implications for Health and Well-being. Curr. Sleep Med. Reports 3 , 104–112 (2017). Hafner, M., Stepanek, M., Taylor, J., Troxel, W. & Stolk, C. Why sleep matters -- the economic costs of insufficient sleep: A cross-country comparative analysis. Rand Heal. Q 6 , 11 (2017). Dawson, D. & Reid, K. Fatigue, alcohol and performance impairment. Nature 388 , 235 (1997). Rajaratnam, S. M. W., Howard, M. E. & Grunstein, R. R. Sleep loss and circadian disruption in shift work: Health burden and management. Med. J. Aust. 199 , S11–S15 (2013). Saksvik, I. B., Bjorvatn, B., Hetland, H., Sandal, G. M. & Pallesen, S. Individual differences in tolerance to shift work--a systematic review. Sleep Med. Rev. 15 , 221–235 (2011). McNamara, K. A. & Robbins, W. A. Shift Work and Sleep Disturbance in the Oil Industry. Work. Heal. Saf. 71 , 118–129 (2023). Härmä, M., Kecklund, G. & Tucker, P. Working hours and health – key research topics in the past and future. 49 , 271–282 (2024). Bastien, C. H., Vallières, A. & Morin, C. M. Validation of the Insomnia Severity Index as an outcome measure for insomnia research. Sleep Med. 2 , 297–307 (2001). Chung, F., Abdullah, H. R. & Liao, P. STOP-bang questionnaire a practical approach to screen for obstructive sleep apnea. Chest 149 , 631–638 (2016). Chiner, E., Arriero, J. M., Signes-Costa, J., Marco, J. & Fuentes, I. Validación de la versión española del test de somnolencia Epworth en pacientes con síndrome de apnea de sueño. Arch. Bronconeumol. 35 , 422–427 (1999). Sanz, J. & García-Vera, M. P. Rendimiento diagnóstico y estructura factorial del inventario de depresión de beck-II (BDI-II). An. Psicol. 29 , 66–75 (2013). Brenlla, M. & Rodríguez, C. Adaptación Argentina Del Inventario de Depresión de Beck (BDI-II) . Inventario de depresión de Beck (Paidós, Buenos Aires, 2006). von Glischinski, M., von Brachel, R. & Hirschfeld, G. How depressed is “depressed”? A systematic review and diagnostic meta-analysis of optimal cut points for the Beck Depression Inventory revised (BDI-II). Qual. Life Res. 28 , 1111–1118 (2019). Roenneberg, T., Wirz-Justice, A. & Merrow, M. Life between clocks: daily temporal patterns of human chronotypes. J. Biol. Rhythms 18 , 80–90 (2003). Tortello, C. et al. Chronotype delay and sleep disturbances shaped by the Antarctic polar night. Sci. Rep. 1–9 (2023) doi:10.1038/s41598-023-43102-0. Fischer, D., Klerman, E. B. & Phillips, A. J. K. Measuring sleep regularity: theoretical properties and practical usage of existing metrics. Sleep 44 , (2021). Phillips, A. J. K. et al. Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing. Sci. Rep. 7 , 1–13 (2017). Mul Fedele, M. L. et al. Multivariate analysis of the impact of sleep and working hours on medical errors: a MICE approach. BMC Public Health 23 , 1–14 (2023). Diez, J. J. et al. Sleep misalignment and circadian rhythm impairment in long-haul bus drivers under a two-up operations system. Sleep Heal. 6 , 374–386 (2020). Kecklund, G. & Axelsson, J. Health consequences of shift work and insufficient sleep. BMJ 355 , (2016). Van Dongen, H., Maislin, G., Mullington, J. & Dinges, D. The cumulative cost of additional wakefulness: Dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep 26 , 117–126 (2003). Chellappa, S. L., Morris, C. J. & Scheer, F. A. J. L. Circadian misalignment increases mood vulnerability in simulated shift work. Sci. Rep. 10 , 1–10 (2020). Watson, N. F. et al. Recommended amount of sleep for a healthy adult: A joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep 38 , 843–844 (2015). Fischer, F. M., De Castro Moreno, C. R., Da Silva Borges, F. N. & Louzada, F. M. Implementation of 12-hour shifts in a Brazilian petrochemical plant: Impact on sleep and alertness. Chronobiol. Int. 17 , 521–537 (2000). Ferguson, S. A. & Dawson, D. 12-h or 8-h shifts? It depends. Sleep Med. Rev. 16 , 519–528 (2012). Sallinen, M. & Kecklund, G. Shift work, sleep, and sleepiness - Differences between shift schedules and systems. Scandinavian Journal of Work, Environment and Health vol. 36 121–133 at https://doi.org/10.5271/sjweh.2900 (2010). Härmä, M. Are long workhours a health risk? Scand. J. Work. Environ. Health 167–169 (2003) doi:10.5271/sjweh.719. Knauth, P. Extended work periods. Ind. Health 45 , 125–136 (2007). Ljoså, C. H. & Lau, B. Shiftwork in the Norwegian petroleum industry: Overcoming difficulties with family and social life a cross sectional study. J. Occup. Med. Toxicol. 4 , 1–10 (2009). Sletten, T. L. et al. The importance of sleep regularity: a consensus statement of the National Sleep Foundation sleep timing and variability panel. Sleep Heal. 9 , 801–820 (2023). Jang, T. W. et al. Circadian rhythm of wrist temperature among shift workers in South Korea: A prospective observational study. Int. J. Environ. Res. Public Health 14 , (2017). Bracci, M. et al. Peripheral skin temperature and circadian biological clock in shift nurses after a day off. Int. J. Mol. Sci. 17 , (2016). Ferreira, L. R. C., Miguel, M. A. L., Figueiredo De Martino, M. M. & Menna-Barreto, L. Circadian rhythm of wrist temperature and night shift-work. Biol. Rhythm Res. 44 , 737–744 (2013). Touitou, Y. et al. Effect of shift work on the night-time secretory patterns of melatonin, prolactin, cortisol and testosterone. Eur. J. Appl. Physiol. Occup. Physiol. 60 , 288–292 (1990). Bourdouxhe, M. A. et al. Aging and shiftwork: the effects of 20 years of rotating 12-hour shifts among petroleum refinery operators. Exp. Aging Res. 25 , 323–329 (1999). Waage, S., Pallesen, S., Moen, B. E. & Bjorvatn, B. Ø. Shift work and age in the offshore petroleum industry. Public Health 251–257 (2010). Juda, M., Vetter, C. & Roenneberg, T. Chronotype modulates sleep duration, sleep quality, and social jet lag in shift-workers. J. Biol. Rhythms 28 , 141–151 (2013). Roenneberg, T., Pilz, L. K., Zerbini, G. & Winnebeck, E. C. Chronotype and social jetlag: A (self-) critical review. Biology vol. 8 at https://doi.org/10.3390/biology8030054 (2019). Vetter, C., Fischer, D., Matera, J. L. & Roenneberg, T. Aligning work and circadian time in shift workers improves sleep and reduces circadian disruption. Curr. Biol. 25 , 907–911 (2015). Gurubhagavatula, I. et al. Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety, and health: Guidance from the American Academy of Sleep Medicine and the Sleep Research Society. Sleep 44 , (2021). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 10 Jul, 2024 Reviews received at journal 04 Jul, 2024 Reviews received at journal 02 Jul, 2024 Reviewers agreed at journal 25 Jun, 2024 Reviewers agreed at journal 19 Jun, 2024 Reviewers invited by journal 08 May, 2024 Editor assigned by journal 02 May, 2024 Submission checks completed at journal 02 May, 2024 First submitted to journal 29 Apr, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4345165","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":299718529,"identity":"6d4aad4c-9608-4e65-8054-37763f976be8","order_by":0,"name":"Malena Mul Fedele","email":"","orcid":"","institution":"Universidad Católica Argentina-CONICET","correspondingAuthor":false,"prefix":"","firstName":"Malena","middleName":"Mul","lastName":"Fedele","suffix":""},{"id":299718531,"identity":"0b4b2683-1a9d-46b4-87b7-db8d12e947bb","order_by":1,"name":"Leandro Casiraghi","email":"","orcid":"","institution":"Universidad de San Andrés-CONICET","correspondingAuthor":false,"prefix":"","firstName":"Leandro","middleName":"","lastName":"Casiraghi","suffix":""},{"id":299718533,"identity":"fd0d153a-6743-4441-80d3-b5f1db771d8f","order_by":2,"name":"Santiago A. Plano","email":"","orcid":"","institution":"Universidad Católica Argentina-CONICET","correspondingAuthor":false,"prefix":"","firstName":"Santiago","middleName":"A.","lastName":"Plano","suffix":""},{"id":299718535,"identity":"c017bd1c-1a30-4eef-b7ba-d836bb1dc120","order_by":3,"name":"Giannina Bellone","email":"","orcid":"","institution":"Universidad Católica Argentina-CONICET","correspondingAuthor":false,"prefix":"","firstName":"Giannina","middleName":"","lastName":"Bellone","suffix":""},{"id":299718538,"identity":"f22cfe53-ea98-4d9f-9116-2ac12a8cbea8","order_by":4,"name":"Diego A. Golombek","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIiWNgGAWjYDCCAwyMB0CkBHsDgwREKIGgFgiS4DlAshaJBCK18J1ffODAx5w7cpIz3xje+PDHjoGfPceA4ece3FokbzxLODhz2zNjaekcY8uZbckMkj1vDBh7nuHWYnDjjMFh3m2HE+dJ55hJ8zYwA0WAtgA9RlBL/TzJM2bSf/7UM9gDtTD+waflfA9YS4K0BI+ZNAPbYQYDiRwDZny2SN5gA/vFcGZPWrFlb9txHokzzwoOy+DRwnf+8MEHH7fdkZc4fnjjjR9/quX425M3PnyDRwsDMDpQAA+IwKeBgYEfv/QoGAWjYBSMAgYGAHYhXWT8P1RHAAAAAElFTkSuQmCC","orcid":"","institution":"Universidad de San Andrés-CONICET","correspondingAuthor":true,"prefix":"","firstName":"Diego","middleName":"A.","lastName":"Golombek","suffix":""},{"id":299718541,"identity":"9ad08556-c1c6-4064-be4c-d8280ac9220a","order_by":5,"name":"Daniel E. Vigo","email":"","orcid":"","institution":"Universidad Católica Argentina-CONICET","correspondingAuthor":false,"prefix":"","firstName":"Daniel","middleName":"E.","lastName":"Vigo","suffix":""}],"badges":[],"createdAt":"2024-04-29 22:10:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4345165/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4345165/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":56277251,"identity":"e9683a3f-9786-48f1-a992-12b015dc7b84","added_by":"auto","created_at":"2024-05-10 20:19:13","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":134324,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSchematic representation of the schedules analyzed.\u003c/strong\u003e “2x2x4” schedule alternated two 12h diurnal work shifts, two 12h nocturnal work shifts and four free-days. “4x4x4” schedule alternated four 12h diurnal work shifts, four free-days, four 12h nocturnal work shifts and four free-days. “Fixed 12 h” schedule consisted of 12-hour diurnal extended work shifts without resting days.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-4345165/v1/ef41a31ab9fb834412a0e2d7.png"},{"id":56277252,"identity":"03be3eba-1f1d-4ee5-896a-2f322ddf4ca6","added_by":"auto","created_at":"2024-05-10 20:19:14","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":602585,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSleep characteristics according to the type of workday and the time of the day for “2x2x4” and “4x4x4” schedules. \u003c/strong\u003eA) Mean ± SEM of sleep hours across different days within the schedule. For both schedules, day 1 represents the initial diurnal work shift. B) Box plot comparing sleep hours between nocturnal and diurnal work shifts for both schedules (mixed-effects repeated measures linear model: \"time of day\" effect: p \u0026lt; 0.001).\u003cstrong\u003e \u003c/strong\u003eC) Box plot of the midpoint of sleep (midsleep) during free days and diurnal work shifts for both schedules (mixed-effects repeated measures linear model: \"type of day\" effect: p \u0026lt; 0.001).\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-4345165/v1/fef32b409b689ec064363caa.png"},{"id":56277253,"identity":"b21a018b-cc9e-4d49-a462-1232551d7cb9","added_by":"auto","created_at":"2024-05-10 20:19:14","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":118120,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSummary of results: comparison between the 2x2x4 and 4x4x4 schedules. \u003c/strong\u003eThe “2x2x4” schedule showed increased nocturnal sleep time after diurnal work, decreased sleep regularity and higher levels of insomnia. Additionally, this shift exhibited increased fatigue impact, lower alertness levels during the night shift, and heightened symptoms of depression. The \"2x2x4\" schedule exhibited lower circadian robustness only when compared to the \"fixed 12-hour schedule\". However, the \"4x4x4\" schedule did not significantly differentiate from either of the other groups. This suggests a greater circadian disruption in the \"2x2x4\" schedule when compared to the \"4x4x4\" schedule as well. Increased sleep in the 2x2x4 scheme was interpreted as a compensatory mechanism for the otherwise compromised circadian rhythm of this shift.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-4345165/v1/3103c812e05bcf1a7fe35dd6.png"},{"id":56277293,"identity":"daeff4f1-cfef-4bbd-80fa-4139055ebf0b","added_by":"auto","created_at":"2024-05-10 20:19:38","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2193416,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4345165/v1/d8d84851-18b3-43ec-b2a3-702a75210fe8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Bridging the gap: examining circadian biology and fatigue alongside work schedules","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe introduction of artificial electric lighting in the 19th century and the restructuring of working times has progressively led to a departure from our usual 24-hour cycles, which respond to the alternating light-dark environment. Society is increasingly dependent on 24-hour, seven-days-a-week operations (the so-called \"24/7 society\") that necessarily require either or both night- or rotating-shifts work. Many industries and services rely on a continuous workforce, including energy production, product manufacturing, transportation, health care, and law enforcement.\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn addition to the adverse effects of long working hours, exposure to nighttime light, and psychosocial factors, the health consequences of shiftwork must first be understood in terms of a fundamental desynchronization between the circadian rhythm of the endogenous biological clock and external synchronizers, the primary one being sunlight. The short-term consequences of shiftwork and nocturnal work are related to an increase in errors at home or in the workplace, leading to an increased risk of incidents and accidents. Some studies conducted in organizations in the United States, France, and the United Kingdom show that the number of workplace accidents related to sleep-related problems can vary from 10\u0026ndash;30% of the total.\u003csup\u003e2\u003c/sup\u003e Furthermore, it has been shown that 17 h of continuous wakefulness has the same effect on the level of reaction as having a blood alcohol level above 0.5 g/l, the legal limit for non-professional drivers in many countries.\u003csup\u003e3\u003c/sup\u003e In the long term, it increases the risk of suffering from various chronic, complex and multifactorial diseases, including cardiovascular, metabolic, neurodegenerative, oncological, immune and mental pathologies, among others.\u003csup\u003e4\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIt has been estimated that approximately 20% of the workforce in industrialized countries is employed in a job requiring rotating shifts work. Although the actual prevalence of clinically significant sleep disorders and excessive daytime sleepiness is unknown, it is estimated to affect between 2\u0026ndash;5% of the general population. The prevalence of shiftwork disorder among rotating and night shift workers has been estimated to be between 10% and 38%. However, these figures do not include early morning or split-shift workers, who may be considered as at-risk groups as well .\u003csup\u003e5\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eCompanies working in the energy sector must operate continuously 24 hours a day, 365 days a year, leading workers to the development of fatigue, a complex state characterized by decreased attention and reduced mental and physical performance, and often accompanied by drowsiness, which can frequently trigger incidents and/or accidents.\u003csup\u003e6\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThere is a need for studies in naturalistic settings to address how to improve the organization of night and shift schedules.\u003csup\u003e7\u003c/sup\u003e We obtained data from workers in a naturalistic environment, with the objective of evaluating the relationship between the specific design of work shifts and the actual amount of sleep achieved. Our analysis provides valuable insights for the design of safer and healthier work schedules, with the potential to enhance worker well-being and overall productivity.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and population\u003c/h2\u003e \u003cp\u003eThis was an observational, analytical, and cross-sectional exploratory study conducted between March 2021 and September 2023. It was conducted in a sample of 44 male shift-workers from an oil company in Argentina, who performed their work in three different schedules, which are detailed in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The three work schedules differ in the distribution of 12-hour extended work shifts and free days: in the \u0026ldquo;2x2x4\u0026rdquo; schedule, workers completed two days of 12 h of daytime shifts followed by two consecutive 12 h night shifts, followed by four work-free days; in the \u0026ldquo;4x4x4\u0026rdquo; schedule, workers alternated four consecutive 12 h daytime shifts and four consecutive 12 h night shifts, flanked by four work-free days; and in the \u0026ldquo;fixed 12h\u0026rdquo; schedule, workers had continuous diurnal work shifts during 40 days (without rest days), associated with the periods in which the plants were shutdown for maintenance.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eMeasurements\u003c/h2\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003eQuestionnaires\u003c/h2\u003e \u003cp\u003eQuestionnaires were completed by participants on an online platform developed for this study. Demographic data, and work, fatigue, alertness and performance characteristics were collected. Overweight was defined as BMI\u0026thinsp;\u0026ge;\u0026thinsp;25, and obesity as BMI\u0026thinsp;\u0026ge;\u0026thinsp;30. Participants reported the distance to work from their homes, whether they had a secondary job, the number of days in which they experienced significant tiredness in the last month, the impact of fatigue in their usual activities in the last year, and their levels of alertness during their work tasks in the last month. They also were asked about coffee and mate consumption. Mate is a traditional South American caffeinated beverage made from steeping dried leaves of the yerba mate plant in hot water.\u003c/p\u003e \u003cp\u003eInsomnia was evaluated through the Insomnia Severity Index (ISI). It consists of seven items that inquire about the severity of sleep onset, sleep maintenance, early morning awakenings, sleep dissatisfaction, interference with daily functioning, noticeability of impairment attributed to sleep difficulties, and distress caused by sleep problems. Each item is rated on a scale from 0 to 4, with higher scores indicating greater severity. The total score ranges from 0 to 28, with higher scores indicating more severe insomnia. Scores are interpreted as follows: no insomnia (0\u0026ndash;7); sub-threshold insomnia (\u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12 CR13\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e); moderate insomnia (\u003cspan additionalcitationids=\"CR16 CR17 CR18 CR19 CR20\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e); and severe insomnia (\u003cspan additionalcitationids=\"CR23 CR24 CR25 CR26 CR27\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e).\u003csup\u003e8\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eSleep apnea was assessed using the STOP-BANG index. It comprises eight yes-or-no questions, targeting the following risk factors associated with sleep apnea: tiredness, observed apnea, high blood pressure, elevated BMI, age, neck circumference, and gender. The total score ranges from 0 to 8, with a low risk indicated by scores of 0\u0026ndash;2, intermediate risk by scores of 3\u0026ndash;4, and high risk by scores of 5 or higher.\u003csup\u003e9\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe Spanish validated version of the Epworth Sleepiness Scale (ESS) was used to measure daytime somnolence. An ESS score between 11 and 14 indicates mild daytime sleepiness, a score between 15 and 17 indicates moderate daytime sleepiness, while a score higher than 18 indicates excessive daytime sleepiness symptoms.\u003csup\u003e10\u003c/sup\u003e\u003c/p\u003e \u003cp\u003ePsycho-affective variables were studied using Spanish validated versions of the Beck Anxiety Inventory (BAI), and the Beck Depression Inventory-II (BDI-II). The BAI is a screening measure of frequency and intensity of anxiety symptoms that contains 21 items on a 4-point Likert scale, with 0 representing 'not at all' and 3 being 'severely'. Scores of 0\u0026ndash;7 are considered \u0026ldquo;minimal anxiety\u0026rdquo;; 8\u0026ndash;15 are \u0026ldquo;mild anxiety\u0026rdquo;; 16\u0026ndash;25 are \u0026ldquo;moderate anxiety\u0026rdquo;; and 26\u0026ndash;63 are \u0026ldquo;severe anxiety\u0026rdquo;.\u003csup\u003e11\u003c/sup\u003e The BDI-II\u003csup\u003e12\u003c/sup\u003e is a widely used self-report questionnaire to evaluate depression symptoms, that contains 21 items with a 4-point Likert scale ranging from 0 (not at all) to 3 (severely). The inventory classifies symptom severity in four categories: minimal (0\u0026ndash;13 pts), mild (14\u0026ndash;19 pts), moderate (20\u0026ndash;28 pts) or severe (29\u0026ndash;63 pts) depression.\u003csup\u003e13\u003c/sup\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003eSleep-wake cycle\u003c/h2\u003e \u003cp\u003eThe sleep-wake cycle was studied using the ActTrust wrist accelerometers (Condor Instruments, Sao Paulo, Brazil). Participants were asked to wear the devices in the nondominant wrist and to complete sleep logs during at least 15 consecutive days. Sleep logs helped us to visually identify \u0026ldquo;in bed\u0026rdquo; episodes in actigraphic recordings. Actigraphy data was analyzed using \u003cem\u003eActStudio\u003c/em\u003e software (Condor Instruments, Sao Paulo, Brazil). The first sleep period after a nocturnal working day was considered as the main sleep period of that day. Other sleep periods starting between 8AM and 7PM and ending before 9PM were considered as naps. The following variables were reported: mean nocturnal sleep between diurnal workdays, mean diurnal sleep after nocturnal workdays, mean nocturnal sleep on free-days, mean total nap duration and mean duration of naps between nocturnal shifts.\u003c/p\u003e \u003cp\u003eMidtime of sleep during free days was computed as a proxy for estimating workers' chronotype.\u003csup\u003e14,15\u003c/sup\u003e For this calculation, we exclusively utilized sleep data from the final two days of the free period since we assume that at that point the sleep debt has already been recovered. Additionally, we computed midsleep times for the nights between diurnal workdays using data from all three nights in between working shifts. As the \u0026ldquo;fixed 12-hour\u0026rdquo; schedule did not have free days during the studied period, the midtime of sleep was only calculated for the other two schedules.\u003c/p\u003e \u003cp\u003eThe sleep regularity index (SRI) was calculated through the formula described by Philips et al. SRI was only calculated for participants with at least eight complete consecutive days of sleep recordings.\u003csup\u003e16,17\u003c/sup\u003e The index represents a measure of the probability (not the probability itself) of a participant being in the same sleep or wake state at two time-points 24 h apart, and can take values that vary from \u0026minus;\u0026thinsp;100 to 100: a person who falls asleep and wakes up precisely at the same times every day will have an SRI of 100; a person who can be asleep or awake randomly throughout days will score 0; finally, in an infrequent albeit possible scenario for our participants, continuous periods of wakefulness (or, theoretically, of sleep as well) of over 24 hours could generate negative SRI values. \u003csup\u003e17\u003c/sup\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003eTemperature circadian rhythm\u003c/h2\u003e \u003cp\u003eThe wrist temperature signal was acquired using the Condor actigraphic devices, with sampling conducted every minute. Values below 25\u0026deg;C were considered as NA. A maximum of 20% missing values and 6-hour contiguous missing values were tolerated. Missing values were substituted using linear interpolation. A 60-minute filter was then applied to the dataset. Finally, a cosinor model featuring a 24-hour main rhythm and a 12-hour harmonic was applied to the data. We reported the amplitude of each rhythm and the rhythm strength (percentage of the total variance explained by the model). \u003csup\u003e18,19\u003c/sup\u003e\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eData analysis\u003c/h2\u003e \u003cp\u003eNumerical variables in the descriptive analysis are shown as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD), and categorical variables as percentage and frequencies (%). For categorical values, differences between groups were assessed using chi-square. For numerical variables, with exception of midtime of sleep during free days, differences between groups were compared by means of a one-way ANOVA followed by a Tukey post-hoc test. For midtime of sleep during free days, differences between \u0026ldquo;2x2x4\u0026rdquo; and \u0026ldquo;4x4x4\u0026rdquo; schedules were assessed using an independent samples t-test.\u003c/p\u003e \u003cp\u003eFinally, for \u0026ldquo;2x2x4\u0026rdquo; and \u0026ldquo;4x4x4\u0026rdquo; schedules we used a mixed-effects linear model to evaluate sleep variations within and between schedules, including sleep duration or midsleep as dependent variables, subject as a random factor and schedule, time of day and type of day as fixed factors.\u003c/p\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003eEthical aspects\u003c/h2\u003e \u003cp\u003e All subjects received detailed information about the procedures and gave written informed consent to participate before the study. The study was performed in accordance with the Declaration of Helsinki and its amendments and was approved by the review board of the Universidad Nacional de Quilmes.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eSociodemographic characteristics\u003c/h2\u003e \u003cp\u003eSociodemographic characteristics and habits are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The sample consisted of 44 male shift-workers: 18 under the \u0026ldquo;2x2x4\u0026rdquo; scheme, 15 under the \u0026ldquo;4x4x4\u0026rdquo; scheme and 11 under the \u0026ldquo;fixed 12h\u0026rdquo; scheme (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Groups did not differ significantly in age, the frequency of overweight, obesity, physical activity, or caffeinated drinks consumption.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eWorkers sociodemographic characteristics and habits according to the schedule worked\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e\u0026ldquo;2x2x4\u0026rdquo; schedule\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c7\" namest=\"c5\"\u003e \u003cp\u003e\u0026ldquo;4x4x4 schedule\u0026rdquo;\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003e\u0026ldquo;fixed 12h\u0026rdquo; schedule\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean age (yr)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.265\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody mass index (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e29.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e27.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e2.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.385\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeight (%):\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNormal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e0.463\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOverweight\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eObesity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhysical activity (%):\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.098\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eLess than 2 hours per week\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e82\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e2 to 4 hours per week\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eMore than 4 hours per week\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCoffee consumption (%):\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e0.640\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNo consumption\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSporadically\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOnce a day\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eTwice a day\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eThree or more times per day\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMate consumption (%):\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNo consumption\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e0.624\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSporadically\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eOnce a day\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eTwice a day\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eThree or more times per day\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eCommute time to work (min)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e61 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSide job (%)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e0.008\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"11\"\u003eShown are mean (SD) or n (%). Differences were assessed through one-way ANOVA followed by Tukey post-hoc test for numerical variables or chi-square for categorical ones. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) Different from the others.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWorkers under \u0026ldquo;4x4x4\u0026rdquo; schedule had longer commute times compared to workers under \u0026ldquo;2x2x4\u0026rdquo; and \u0026ldquo;fixed 12h\u0026rdquo; schedules (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; post-hoc test: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 for \u0026ldquo;4x4x4\u0026rdquo; schedule vs. \u0026ldquo;2x2x4\u0026rdquo; schedule and p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 for \u0026ldquo;4x4x4\u0026rdquo; schedule vs. \u0026ldquo;fixed 12h\u0026rdquo; schedule). Additionally, a higher percentage of workers on \u0026ldquo;4x4x4\u0026rdquo; schedule reported holding a secondary job (p\u0026thinsp;=\u0026thinsp;0.008) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eSleep characteristics\u003c/h2\u003e \u003cp\u003eSleep characteristics of the participants are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The mean duration of nocturnal sleep on workdays was 5h:42m for workers under the \u0026ldquo;2x2x4\u0026rdquo; schedule, 5h:10m for those under the \u0026ldquo;4x4x4\u0026rdquo; schedule, and 6h:19m for those under the \u0026ldquo;fixed 12h\u0026rdquo; schedule. Nocturnal sleep for workers under the \u0026ldquo;4x4x4\u0026rdquo; schedule was more than an hour shorter than for workers under the \u0026ldquo;fixed 12h\u0026rdquo; schedule (p\u0026thinsp;=\u0026thinsp;0.003, post-hoc test: p\u0026thinsp;=\u0026thinsp;0.002) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eWorkers sleep characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e\u0026ldquo;2x2x4\u0026rdquo; schedule\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c7\" namest=\"c5\"\u003e \u003cp\u003e\u0026ldquo;4x4x4 schedule\u0026rdquo;\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003e\u0026ldquo;fixed 12h\u0026rdquo; schedule\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean nocturnal sleep duration between diurnal workdays (hh:mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e05:42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e00:46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e05:10 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e00:53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e06:19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e00:38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e0.003\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean diurnal sleep duration after nocturnal workdays (hh:mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e03:53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e00:53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e03:26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e01:17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.257\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean nocturnal sleep duration on free-days (hh:mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e08:03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e00:55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e07:27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e00:43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e0.041\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean total nap duration (hh:mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e01:39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e00:32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e01:28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e00:21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.371\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean duration of naps between nocturnal shifts (hh:mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e01:44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e00:37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e01:32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e00:21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.339\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMidsleep between diurnal workdays (hh:mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e02:43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e00:40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e02:28 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e00:33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e02:52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e00:42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMidsleep after nocturnal workdays (hh:mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10:52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e01:42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e10:47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e01:26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.766\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMidsleep on free-days (hh:mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e05:22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e02:09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e04:50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e01:30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.197\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSleep regularity index\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e39 (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e54 (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e72 (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSleepiness (ESS)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.466\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsomnia (ISI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.2 (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e6.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e4.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e0.017\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eApnea (STOP BANG, %)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.873\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eHigh risk\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eIntermediate risk\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eLow risk\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"11\"\u003eShown are mean (SD) or n (%). Differences were assessed through one-way ANOVA followed by Tukey post-hoc test for numerical variables or chi-square test for categorical ones. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) Different from \u0026ldquo;fixed 12h\u0026rdquo;. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) Different between each other. (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) Different from \u0026ldquo;2x2x4\u0026rdquo;. ESS: Epworth sleepiness scale. ISI: Insomnia severity index.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWe did not find differences in diurnal sleep after nocturnal shifts between participants under the \u0026ldquo;2x2x4\u0026rdquo; and the \u0026ldquo;4x4x4\u0026rdquo; schedules (\u0026ldquo;fixed 12h\u0026rdquo; schedule does not include nocturnal workdays). Regarding sleep during free days, workers under the \u0026ldquo;4x4x4\u0026rdquo; schedule slept 30 minutes less than those under the \u0026ldquo;2x2x4\u0026rdquo; schedule (p\u0026thinsp;=\u0026thinsp;0.041). We found that 73% of workers in the \u0026ldquo;2x2x4\u0026rdquo; schedule and 67% under the \u0026ldquo;4x4x4\u0026rdquo; schedule took naps before and between nocturnal workdays (p\u0026thinsp;=\u0026thinsp;ns ), and we did not find differences in nap duration between schedules (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eNocturnal sleep midsleep times on free days was similar between \u0026ldquo;2x2x4\u0026rdquo; and \u0026ldquo;4x4x4\u0026rdquo; schedules. On workdays, 2x2x4 midsleep for \u0026ldquo;4x4x4\u0026rdquo; schedule was significantly earlier than for \u0026ldquo;fixed 12h\u0026rdquo; schedule (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Regarding sleep regularity, we determined a significantly lower SRI for workers under the \u0026ldquo;2x2x4\u0026rdquo; schedule compared to \u0026ldquo;4x4x4\u0026rdquo; and \u0026ldquo;fixed 12h\u0026ldquo; schedules, and for workers under the \u0026ldquo;4x4x4\u0026rdquo; schedule compared to the \u0026ldquo;fixed 12h\u0026rdquo; schedule (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, post-hoc test: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 for all contrasts) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA shows sleep duration across the \u0026ldquo;2x2x4\u0026rdquo; and \u0026ldquo;4x4x4\u0026rdquo; schedules. Sleep duration during the day after nocturnal work shifts was significantly shorter than sleep during the night between diurnal shifts for both schedules (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB, \"time of day\" effect: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Also, midsleep was earlier on diurnal working days compared to free days for both schedules (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC, \"type of day\" effect: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFinally, we did not find differences in diurnal sleepiness or sleep apnea risk between the schedules. However, workers under the \u0026ldquo;2x2x4\u0026rdquo; schedule showed higher scores on the Insomnia Severity Index than those under the \u0026ldquo;4x4x4\u0026rdquo; one (p\u0026thinsp;=\u0026thinsp;0.017, post-hoc test: p\u0026thinsp;=\u0026thinsp;0.024) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eTemperature circadian rhythm\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the results of the circadian temperature rhythm analysis. Sample sizes decreased for all groups due to the acceptance criteria for maximum NA values, which did not significantly differ between groups. Significant differences were observed for the 12-hour amplitude of the temperature rhythm and the percentage of variance explained by the model. The \u0026ldquo;2x2x4\u0026rdquo; schedule differed from the \u0026ldquo;fixed 12h\u0026rdquo; schedule, while the \u0026ldquo;4x4x4\u0026rdquo; schedule presented intermediate values between both (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eCircadian temperature rhythm analysis\u003c/b\u003e \u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e\u0026ldquo;2x2x4\u0026rdquo; schedule\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;10)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003e\u0026ldquo;4x4x4\u0026rdquo; schedule\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;11)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e\u0026ldquo;fixed 12 h\u0026rdquo; schedule\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRecord length (hr)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e324\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e357\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e320\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.115\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e% NA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.148\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMax. cont. NA (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e123\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e108\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e150\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e107\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.420\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAmp 24 hr (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.258\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAmp 12 hr (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.030 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRhythm strength (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e34.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e18.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.005 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e\u003cp\u003eShown are mean (SD). One-way ANOVA followed by Tukey post-hoc test. Max. cont. NA: maximum contiguous NA values; rhythm strength: percent of the variance explained by the model. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) \u0026ldquo;fixed 12 h\u0026rdquo; differs from \u0026ldquo;2x2x4\u0026rdquo;.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eFatigue impact, alertness and wellbeing\u003c/h2\u003e \u003cp\u003eFatigue impact, alertness and wellbeing are presented in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Workers under the \u0026ldquo;fixed 12h\u0026rdquo; schedule reported a higher number of days with significant tiredness in the last month compared to those under the \u0026ldquo;4x4x4\u0026rdquo; schedule (p\u0026thinsp;=\u0026thinsp;0.022, post-hoc test: p\u0026thinsp;=\u0026thinsp;0.019). Workers under the \u0026ldquo;4x4x4\u0026rdquo; schedule reported being less negatively impacted by fatigue in their ability to learn new tasks (p\u0026thinsp;=\u0026thinsp;0.009) and overall job satisfaction (p\u0026thinsp;=\u0026thinsp;0.009) compared to workers under the \u0026ldquo;2x2x4\u0026rdquo; and \u0026ldquo;fixed 12h\u0026rdquo; schedules; and in their relationships with coworkers (p\u0026thinsp;=\u0026thinsp;0.017) compared to workers under the \u0026ldquo;fixed 12h\u0026rdquo; schedule (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eReported fatigue and its impact on shiftworkers performance. relationships and wellbeing\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003e\u0026ldquo;2x2x4\u0026rdquo; schedule\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c7\" namest=\"c5\"\u003e \u003cp\u003e\u0026ldquo;4x4x4 schedule\u0026rdquo;\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c10\" namest=\"c8\"\u003e \u003cp\u003e\u0026ldquo;fixed 12h\u0026rdquo; schedule\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eVariable\u003c/b\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eValid n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eMean/n\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cem\u003eSD/%\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReported fatigue negative impact on\u0026hellip;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026hellip; performance at work\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e0.085\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNever\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eRarely\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSometimes\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eFrequently\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026hellip; learning new tasks\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003e0.009\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNever\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eRarely\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSometimes\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eFrequently\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026hellip; their overall employee satisfaction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e\u003cb\u003e0.009\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNever\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eRarely\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSometimes\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eFrequently\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026hellip; their co-workers safety\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.332\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNever\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eRarely\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSometimes\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eFrequently\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026hellip; their own safety\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.314\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNever\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eRarely\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSometimes\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eFrequently\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026hellip; the relationship with co-workers\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e\u003cb\u003e0.017\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNever\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eRarely\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSometimes\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eFrequently\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReported level of alertness to carry out their work task in the \u0026hellip;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026hellip; middle of the day\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"5\" rowspan=\"6\"\u003e \u003cp\u003e0.169\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNot at all rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003ePoorly rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSomewhat rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eFairly rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e46\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eVery rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026hellip; middle of the night\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\" morerows=\"5\" rowspan=\"6\"\u003e \u003cp\u003e\u003cb\u003e0.028\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eNot at all rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003ePoorly rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSomewhat rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eFairly rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eVery rested and alert\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cem\u003eN/A\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSignificant tiredness (# days)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2 (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e0.022\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnxiety (BAI score)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e3.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.095\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDepression (BDI II score)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.9 (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e5.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u003cb\u003e0.005\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"11\"\u003eShown are mean (SD) or n (%). Differences were assessed through one-way ANOVA followed by Tukey post-hoc test for numerical variables or chi-square test for categorical ones. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) Different from \u0026ldquo;12 h fixed\u0026rdquo;; (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) Different from the others.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWe did not find differences between schedules in the reported levels of alertness in the middle of diurnal workdays, but workers under the \u0026ldquo;2x2x4\u0026rdquo; schedule reported lower levels of alertness in the middle of nocturnal work shifts compared to those under the \u0026ldquo;4x4x4\u0026rdquo; schedule (p\u0026thinsp;=\u0026thinsp;0.028) (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eFinally, we noted higher scores for depression symptoms for workers under the \u0026ldquo;2x2x4\u0026rdquo; and \u0026ldquo;fixed 12h\u0026rdquo; schedules compared to those under the \u0026ldquo;4x4x4\u0026rdquo; schedule (p\u0026thinsp;=\u0026thinsp;0.005), while anxiety levels were similar (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThe scheduling of shiftwork depends on several factors, including productivity, costs, and workers\u0026rsquo; wellbeing. Indeed, shiftwork has emerged as one of the key translational opportunities for circadian research, together with a chronobiological approach to health issues. Among the different variables that can be optimized is the number of days under nocturnal or diurnal tasks and the rest periods between them. This is a complex issue that should take into account several variables, balancing productivity, presenteeism, accident and incident rates, health and the impact on the social life of workers.\u003csup\u003e1\u003c/sup\u003e Since there is a clear link between shift duration, sleep, and health outcomes,\u003csup\u003e20\u003c/sup\u003e and the effects of continuous sleep deprivation and irregularity is cumulative,\u003csup\u003e21\u003c/sup\u003e a correct decision in terms of the schedule might have long-lasting consequences. Indeed, many other variables contribute to both productivity and wellbeing during shiftwork, including environmental factors (i.e., illumination, feeding schedules, etc.), individual characteristics such as chronotype and even commuting time and distance, and the nature of the work being performed, as well as stress and inherent working hazards. Since shiftwork also affects mood vulnerability,\u003csup\u003e18,22\u003c/sup\u003e it is not surprising that such routine impacts both co-workers and their family relationships.\u003c/p\u003e \u003cp\u003eHere we examined the effect of three different working schedules on the sleep-wake performance of workers in the logistics branch of one of the biggest oil companies in South America. In all cases, the duration of sleep during the resting period was significantly less than the recommended 7 hours of nocturnal sleep.\u003csup\u003e23\u003c/sup\u003e The \u0026ldquo;2x2x4\u0026rdquo; schedule showed increased nocturnal sleep time after diurnal work, decreased sleep regularity and a dampened circadian temperature rhythm. Additionally, this shift exhibited higher levels of insomnia, increased fatigue impact, lower alertness levels, and heightened symptoms of depression (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eParticipants in our study only worked 12-h shifts. There is much discussion regarding their advantage over 8-h shifts; including an increased sleep opportunity during rest days. However, some reports state that this schedule might decrease alertness\u003csup\u003e24\u003c/sup\u003e and deteriorate domestic life.\u003csup\u003e25\u003c/sup\u003e While there is a clear consensus in the fact that any shiftwork schedule will result in circadian and sleep disruption, especially at the extremes of very long or very short types of rotation, there is no clear effect of switching between 8- and 12-h shifts.\u003csup\u003e26\u003c/sup\u003e Since oil industry must rely on 24/7 activities, the most usual schedule in companies around the world involves 12-h shifts for 2 or 4 consecutive days (in contrast to the previously implemented 8-h shifts system, with less frequent rotation). However, long work hours are associated with short sleep duration, sleep disruption, and decreased alertness.\u003csup\u003e24,27,28\u003c/sup\u003e The impact of shiftwork schedules in the oil industry on the domestic and social life of workers has also been highlighted elsewhere.\u003csup\u003e29\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe disruption of sleep patterns and circadian temperature rhythms observed in workers under the \"2x2x4\" scheme may probably be attributed to the shorter duration of shifts. Sleep regularity, a measure of the consistency of day-to-day variability in sleep\u0026ndash;wake timing \u0026ndash; has recently received much attention, in terms of its importance for health, safety and productivity). It is known that fluctuations in both environmental and behavioral factors associated with variability in sleep timing can induce circadian disruption\u003csup\u003e30\u003c/sup\u003e and, in turn, sleep disturbances.\u003csup\u003e4\u003c/sup\u003e In this regard, the increased sleep duration observed in this group could be explained as a compensatory mechanism for the disruption of circadian rhythms. While extending sleep on non-work days is a common human pattern to counter sleep deficiency on work days,\u003csup\u003e30\u003c/sup\u003e this practice may not be sufficient in the 2x4 schedule, resulting in additional sleep during work days. Indeed, in a previous study involving long-haul bus drivers working with a two-up operations system, we reported that workers under high fatigue risk working schedules showed increased sleep duration during the trips on the bus.\u003csup\u003e19\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe results obtained from the circadian analysis of temperature reinforce what has been discussed so far. The \"2x2x4\" schedule exhibited lower circadian robustness compared to the \"fixed 12-hour\u0026rdquo; schedule, while the \"4x4x4\" schedule showed intermediate values, without significantly differentiating from the other groups. Taken together, this reveals a greater circadian disruption in the \"2x2x4\" schedule compared to the \"4x4x4\" one. These results are also consistent with the disruption of the expression of the circadian rhythm of wrist temperature by shift-work reported by our group in drivers exposed to high-risk working schedules\u003csup\u003e19\u003c/sup\u003e and by others. \u003csup\u003e31\u0026ndash;33\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn our work, we observed that workers from \u0026ldquo;2x2x4\u0026rdquo; the schedule reported a higher number of days with significant tiredness in the last month, a greater negative impact of fatigue on their daily activities, and more depression symptoms. Also, these workers reported lower levels of alertness in the middle of night shifts than workers from the \u0026ldquo;4x4x4\u0026rdquo; schedule. This aligns with the circadian disruption observed in this group, known to potentially result in sleep disturbances, sleep medication consumption, persistent fatigue and mood disorders, and/or burn out, which could compromise safety and health.\u003csup\u003e4\u003c/sup\u003e In fact, a report from the 1990s\u003csup\u003e34\u003c/sup\u003e investigated oil refinery workers during their night shift, finding significant changes in endocrine rhythms, with a lower amplitude for cortisol and higher peaks for melatonin. It is also well-known that the number of years spent on shiftwork in this industry further affects sleep, health, and productivity.\u003csup\u003e35,36\u003c/sup\u003e More recently, studies have demonstrated that impaired sleep quality and shorter sleep duration in oil activity shift workers are associated with increased fatigue-related incidents.\u003csup\u003e6\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eWe also considered chronotype, which might affect the outcome of shift workers, with certain advantages for late-types.\u003csup\u003e37\u003c/sup\u003e In our case, we did not find significant differences in midsleep on free days between Schedules \u0026ldquo;2x2x4\u0026rdquo; and \u0026ldquo;4x4x4\u0026rdquo;. The midpoint of sleep on free days for \u0026ldquo;2x2x4\u0026rdquo; schedule was at 05:22 am, while for \u0026ldquo;4x4x4\u0026rdquo; schedule it was at 04:50 am, both corresponding to slightly late chronotypes;\u003csup\u003e38\u003c/sup\u003e however, it should be noted that the Argentinian is a particularly late culture. Since the alignment of individual chronotype with working hours might reduce circadian disruption,\u003csup\u003e39\u003c/sup\u003e more data is needed to assess the impact of this variable on performance and wellness in this particular industry.\u003c/p\u003e \u003cp\u003eAccording to the guiding principles of the American Academy of Sleep Medicine and the Sleep Research Society (2021),\u003csup\u003e40\u003c/sup\u003e the duration of working shifts is linked to adverse performance, safety, and health outcomes, and several countermeasures are proposed to overcome such adverse consequences. The first of these measures is to \u0026ldquo;schedule interventions to maximize daily sleep opportunity, consistently align work with the biological drive for wakefulness and increase time for recovery after extended duties or multiple shifts.\u0026rdquo; Here we have compared three different shiftwork schedules for the oil industry, finding that a \u0026ldquo;2x2x4\u0026rdquo; shift work schedule showed decreased sleep regularity and a dampened circadian temperature rhythm, associated with higher levels of insomnia, increased fatigue impact, lower alertness levels, and heightened symptoms of depression. There are several confounding factors that should be considered, and were not addressed here, to fully understand the impact of shift work design on sleep, alertness and fatigue. Among these are the nature of tasks performed, the environmental conditions both at work and at home, and the types of jobs. However, we believe that our results contribute to a further understanding of the optimal working conditions that our 24/7 society demands to achieve improved outcomes in health, wellness, and productivity, representing a clear case for translational circadian research.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eMMF, LC, SAP and GB performed the field recordings and surveys. MMF, LC, DAG and DEG wrote the main manuscript text and prepared the figures and tables. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eACKNOWLEDGEMENTS\u003c/h2\u003e \u003cp\u003e We are very grateful to the workers and management of YPF, the national oil company, for participating in this study and providing help and advice with the design of the project. This work was partially financed by a grant from Agencia Nacional de Promoci\u0026oacute;n Cient\u0026iacute;fica y Tecnol\u0026oacute;gica (ANPCyT), PICT 2020\u0026ndash;02452. MMF, LPG, SAP, DEV and DAG are members of the National Research Council (CONICET).\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData is provided within the manuscript. Raw data will be provided upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eJames, S. M., Honn, K. A., Gaddameedhi, S. \u0026amp; Van Dongen, H. P. A. Shift Work: Disrupted Circadian Rhythms and Sleep\u0026mdash;Implications for Health and Well-being. \u003cem\u003eCurr. Sleep Med. Reports\u003c/em\u003e \u003cstrong\u003e3\u003c/strong\u003e, 104\u0026ndash;112 (2017).\u003c/li\u003e\n\u003cli\u003eHafner, M., Stepanek, M., Taylor, J., Troxel, W. \u0026amp; Stolk, C. Why sleep matters -- the economic costs of insufficient sleep: A cross-country comparative analysis. \u003cem\u003eRand Heal. Q\u003c/em\u003e \u003cstrong\u003e6\u003c/strong\u003e, 11 (2017).\u003c/li\u003e\n\u003cli\u003eDawson, D. \u0026amp; Reid, K. Fatigue, alcohol and performance impairment. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e388\u003c/strong\u003e, 235 (1997).\u003c/li\u003e\n\u003cli\u003eRajaratnam, S. M. W., Howard, M. E. \u0026amp; Grunstein, R. R. Sleep loss and circadian disruption in shift work: Health burden and management. \u003cem\u003eMed. J. Aust.\u003c/em\u003e \u003cstrong\u003e199\u003c/strong\u003e, S11\u0026ndash;S15 (2013).\u003c/li\u003e\n\u003cli\u003eSaksvik, I. B., Bjorvatn, B., Hetland, H., Sandal, G. M. \u0026amp; Pallesen, S. Individual differences in tolerance to shift work--a systematic review. \u003cem\u003eSleep Med. Rev.\u003c/em\u003e \u003cstrong\u003e15\u003c/strong\u003e, 221\u0026ndash;235 (2011).\u003c/li\u003e\n\u003cli\u003eMcNamara, K. A. \u0026amp; Robbins, W. A. Shift Work and Sleep Disturbance in the Oil Industry. \u003cem\u003eWork. Heal. Saf.\u003c/em\u003e \u003cstrong\u003e71\u003c/strong\u003e, 118\u0026ndash;129 (2023).\u003c/li\u003e\n\u003cli\u003eH\u0026auml;rm\u0026auml;, M., Kecklund, G. \u0026amp; Tucker, P. Working hours and health \u0026ndash; key research topics in the past and future. \u003cstrong\u003e49\u003c/strong\u003e, 271\u0026ndash;282 (2024).\u003c/li\u003e\n\u003cli\u003eBastien, C. H., Valli\u0026egrave;res, A. \u0026amp; Morin, C. M. Validation of the Insomnia Severity Index as an outcome measure for insomnia research. \u003cem\u003eSleep Med.\u003c/em\u003e \u003cstrong\u003e2\u003c/strong\u003e, 297\u0026ndash;307 (2001).\u003c/li\u003e\n\u003cli\u003eChung, F., Abdullah, H. R. \u0026amp; Liao, P. STOP-bang questionnaire a practical approach to screen for obstructive sleep apnea. \u003cem\u003eChest\u003c/em\u003e \u003cstrong\u003e149\u003c/strong\u003e, 631\u0026ndash;638 (2016).\u003c/li\u003e\n\u003cli\u003eChiner, E., Arriero, J. M., Signes-Costa, J., Marco, J. \u0026amp; Fuentes, I. Validaci\u0026oacute;n de la versi\u0026oacute;n espa\u0026ntilde;ola del test de somnolencia Epworth en pacientes con s\u0026iacute;ndrome de apnea de sue\u0026ntilde;o. \u003cem\u003eArch. Bronconeumol.\u003c/em\u003e \u003cstrong\u003e35\u003c/strong\u003e, 422\u0026ndash;427 (1999).\u003c/li\u003e\n\u003cli\u003eSanz, J. \u0026amp; Garc\u0026iacute;a-Vera, M. P. Rendimiento diagn\u0026oacute;stico y estructura factorial del inventario de depresi\u0026oacute;n de beck-II (BDI-II). \u003cem\u003eAn. Psicol.\u003c/em\u003e \u003cstrong\u003e29\u003c/strong\u003e, 66\u0026ndash;75 (2013).\u003c/li\u003e\n\u003cli\u003eBrenlla, M. \u0026amp; Rodr\u0026iacute;guez, C. \u003cem\u003eAdaptaci\u0026oacute;n Argentina Del Inventario de Depresi\u0026oacute;n de Beck (BDI-II)\u003c/em\u003e. \u003cem\u003eInventario de depresi\u0026oacute;n de Beck\u003c/em\u003e (Paid\u0026oacute;s, Buenos Aires, 2006).\u003c/li\u003e\n\u003cli\u003evon Glischinski, M., von Brachel, R. \u0026amp; Hirschfeld, G. How depressed is \u0026ldquo;depressed\u0026rdquo;? A systematic review and diagnostic meta-analysis of optimal cut points for the Beck Depression Inventory revised (BDI-II). \u003cem\u003eQual. Life Res.\u003c/em\u003e \u003cstrong\u003e28\u003c/strong\u003e, 1111\u0026ndash;1118 (2019).\u003c/li\u003e\n\u003cli\u003eRoenneberg, T., Wirz-Justice, A. \u0026amp; Merrow, M. Life between clocks: daily temporal patterns of human chronotypes. \u003cem\u003eJ. Biol. Rhythms\u003c/em\u003e \u003cstrong\u003e18\u003c/strong\u003e, 80\u0026ndash;90 (2003).\u003c/li\u003e\n\u003cli\u003eTortello, C. \u003cem\u003eet al.\u003c/em\u003e Chronotype delay and sleep disturbances shaped by the Antarctic polar night. \u003cem\u003eSci. Rep.\u003c/em\u003e 1\u0026ndash;9 (2023) doi:10.1038/s41598-023-43102-0.\u003c/li\u003e\n\u003cli\u003eFischer, D., Klerman, E. B. \u0026amp; Phillips, A. J. K. Measuring sleep regularity: theoretical properties and practical usage of existing metrics. \u003cem\u003eSleep\u003c/em\u003e \u003cstrong\u003e44\u003c/strong\u003e, (2021).\u003c/li\u003e\n\u003cli\u003ePhillips, A. J. K. \u003cem\u003eet al.\u003c/em\u003e Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing. \u003cem\u003eSci. Rep.\u003c/em\u003e \u003cstrong\u003e7\u003c/strong\u003e, 1\u0026ndash;13 (2017).\u003c/li\u003e\n\u003cli\u003eMul Fedele, M. L. \u003cem\u003eet al.\u003c/em\u003e Multivariate analysis of the impact of sleep and working hours on medical errors: a MICE approach. \u003cem\u003eBMC Public Health\u003c/em\u003e \u003cstrong\u003e23\u003c/strong\u003e, 1\u0026ndash;14 (2023).\u003c/li\u003e\n\u003cli\u003eDiez, J. J. \u003cem\u003eet al.\u003c/em\u003e Sleep misalignment and circadian rhythm impairment in long-haul bus drivers under a two-up operations system. \u003cem\u003eSleep Heal.\u003c/em\u003e \u003cstrong\u003e6\u003c/strong\u003e, 374\u0026ndash;386 (2020).\u003c/li\u003e\n\u003cli\u003eKecklund, G. \u0026amp; Axelsson, J. Health consequences of shift work and insufficient sleep. \u003cem\u003eBMJ\u003c/em\u003e \u003cstrong\u003e355\u003c/strong\u003e, (2016).\u003c/li\u003e\n\u003cli\u003eVan Dongen, H., Maislin, G., Mullington, J. \u0026amp; Dinges, D. The cumulative cost of additional wakefulness: Dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. \u003cem\u003eSleep\u003c/em\u003e \u003cstrong\u003e26\u003c/strong\u003e, 117\u0026ndash;126 (2003).\u003c/li\u003e\n\u003cli\u003eChellappa, S. L., Morris, C. J. \u0026amp; Scheer, F. A. J. L. Circadian misalignment increases mood vulnerability in simulated shift work. \u003cem\u003eSci. Rep.\u003c/em\u003e \u003cstrong\u003e10\u003c/strong\u003e, 1\u0026ndash;10 (2020).\u003c/li\u003e\n\u003cli\u003eWatson, N. F. \u003cem\u003eet al.\u003c/em\u003e Recommended amount of sleep for a healthy adult: A joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. \u003cem\u003eSleep\u003c/em\u003e \u003cstrong\u003e38\u003c/strong\u003e, 843\u0026ndash;844 (2015).\u003c/li\u003e\n\u003cli\u003eFischer, F. M., De Castro Moreno, C. R., Da Silva Borges, F. N. \u0026amp; Louzada, F. M. Implementation of 12-hour shifts in a Brazilian petrochemical plant: Impact on sleep and alertness. \u003cem\u003eChronobiol. Int.\u003c/em\u003e \u003cstrong\u003e17\u003c/strong\u003e, 521\u0026ndash;537 (2000).\u003c/li\u003e\n\u003cli\u003eFerguson, S. A. \u0026amp; Dawson, D. 12-h or 8-h shifts? It depends. \u003cem\u003eSleep Med. Rev.\u003c/em\u003e \u003cstrong\u003e16\u003c/strong\u003e, 519\u0026ndash;528 (2012).\u003c/li\u003e\n\u003cli\u003eSallinen, M. \u0026amp; Kecklund, G. Shift work, sleep, and sleepiness - Differences between shift schedules and systems. \u003cem\u003eScandinavian Journal of Work, Environment and Health\u003c/em\u003e vol. 36 121\u0026ndash;133 at https://doi.org/10.5271/sjweh.2900 (2010).\u003c/li\u003e\n\u003cli\u003eH\u0026auml;rm\u0026auml;, M. Are long workhours a health risk? \u003cem\u003eScand. J. Work. Environ. Health\u003c/em\u003e 167\u0026ndash;169 (2003) doi:10.5271/sjweh.719.\u003c/li\u003e\n\u003cli\u003eKnauth, P. Extended work periods. \u003cem\u003eInd. Health\u003c/em\u003e \u003cstrong\u003e45\u003c/strong\u003e, 125\u0026ndash;136 (2007).\u003c/li\u003e\n\u003cli\u003eLjos\u0026aring;, C. H. \u0026amp; Lau, B. Shiftwork in the Norwegian petroleum industry: Overcoming difficulties with family and social life a cross sectional study. \u003cem\u003eJ. Occup. Med. Toxicol.\u003c/em\u003e \u003cstrong\u003e4\u003c/strong\u003e, 1\u0026ndash;10 (2009).\u003c/li\u003e\n\u003cli\u003eSletten, T. L. \u003cem\u003eet al.\u003c/em\u003e The importance of sleep regularity: a consensus statement of the National Sleep Foundation sleep timing and variability panel. \u003cem\u003eSleep Heal.\u003c/em\u003e \u003cstrong\u003e9\u003c/strong\u003e, 801\u0026ndash;820 (2023).\u003c/li\u003e\n\u003cli\u003eJang, T. W. \u003cem\u003eet al.\u003c/em\u003e Circadian rhythm of wrist temperature among shift workers in South Korea: A prospective observational study. \u003cem\u003eInt. J. Environ. Res. Public Health\u003c/em\u003e \u003cstrong\u003e14\u003c/strong\u003e, (2017).\u003c/li\u003e\n\u003cli\u003eBracci, M. \u003cem\u003eet al.\u003c/em\u003e Peripheral skin temperature and circadian biological clock in shift nurses after a day off. \u003cem\u003eInt. J. Mol. Sci.\u003c/em\u003e \u003cstrong\u003e17\u003c/strong\u003e, (2016).\u003c/li\u003e\n\u003cli\u003eFerreira, L. R. C., Miguel, M. A. L., Figueiredo De Martino, M. M. \u0026amp; Menna-Barreto, L. Circadian rhythm of wrist temperature and night shift-work. \u003cem\u003eBiol. Rhythm Res.\u003c/em\u003e \u003cstrong\u003e44\u003c/strong\u003e, 737\u0026ndash;744 (2013).\u003c/li\u003e\n\u003cli\u003eTouitou, Y. \u003cem\u003eet al.\u003c/em\u003e Effect of shift work on the night-time secretory patterns of melatonin, prolactin, cortisol and testosterone. \u003cem\u003eEur. J. Appl. Physiol. Occup. Physiol.\u003c/em\u003e \u003cstrong\u003e60\u003c/strong\u003e, 288\u0026ndash;292 (1990).\u003c/li\u003e\n\u003cli\u003eBourdouxhe, M. A. \u003cem\u003eet al.\u003c/em\u003e Aging and shiftwork: the effects of 20 years of rotating 12-hour shifts among petroleum refinery operators. \u003cem\u003eExp. Aging Res.\u003c/em\u003e \u003cstrong\u003e25\u003c/strong\u003e, 323\u0026ndash;329 (1999).\u003c/li\u003e\n\u003cli\u003eWaage, S., Pallesen, S., Moen, B. E. \u0026amp; Bjorvatn, B. \u0026Oslash;. Shift work and age in the offshore petroleum industry. \u003cem\u003ePublic Health\u003c/em\u003e 251\u0026ndash;257 (2010).\u003c/li\u003e\n\u003cli\u003eJuda, M., Vetter, C. \u0026amp; Roenneberg, T. Chronotype modulates sleep duration, sleep quality, and social jet lag in shift-workers. \u003cem\u003eJ. Biol. Rhythms\u003c/em\u003e \u003cstrong\u003e28\u003c/strong\u003e, 141\u0026ndash;151 (2013).\u003c/li\u003e\n\u003cli\u003eRoenneberg, T., Pilz, L. K., Zerbini, G. \u0026amp; Winnebeck, E. C. Chronotype and social jetlag: A (self-) critical review. \u003cem\u003eBiology\u003c/em\u003e vol. 8 at https://doi.org/10.3390/biology8030054 (2019).\u003c/li\u003e\n\u003cli\u003eVetter, C., Fischer, D., Matera, J. L. \u0026amp; Roenneberg, T. Aligning work and circadian time in shift workers improves sleep and reduces circadian disruption. \u003cem\u003eCurr. Biol.\u003c/em\u003e \u003cstrong\u003e25\u003c/strong\u003e, 907\u0026ndash;911 (2015).\u003c/li\u003e\n\u003cli\u003eGurubhagavatula, I. \u003cem\u003eet al.\u003c/em\u003e Guiding principles for determining work shift duration and addressing the effects of work shift duration on performance, safety, and health: Guidance from the American Academy of Sleep Medicine and the Sleep Research Society. \u003cem\u003eSleep\u003c/em\u003e \u003cstrong\u003e44\u003c/strong\u003e, (2021).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"npj-biological-timing-and-sleep","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [npj Biological Timing and Sleep](https://www.nature.com/npjbts)","snPcode":"44323","submissionUrl":"https://submission.springernature.com/new-submission/44323/3","title":"npj Biological Timing and Sleep","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"shiftwork, fatigue, working schedules, sleep","lastPublishedDoi":"10.21203/rs.3.rs-4345165/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4345165/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe socio-cultural, industrial, and business demands of our current society require us to be active 24 hours a day, 7 days a week. This phenomenon implies working conditions that lead employees to perform their tasks in rotating shifts, during nighttime hours, and for extended shifts, thereby disrupting their biological rhythms, most fundamentally their sleep patterns. There is a need for naturalistic studies to evaluate the relationship between the specific design of work shifts and the actual amount of achievedsleep.\u003c/p\u003e \u003cp\u003eTo achieve this goal, we conducted a comprehensive study involving employees of the logistic chain of an oil company in Argentina. We compared three different types of work schedules that encompassed extended and rotating shifts work: 1) one in which workers completed two days of 12 h of daytime shifts followed by two consecutive 12 h night shifts, followed by four work-free days(\u0026ldquo;2x2x4x4x4\u0026rdquo; schedule), 2) one in which workers alternated four consecutive 12 h daytime shifts and four consecutive 12 h night shifts, flanked by four work-free days (\u0026ldquo;4x4x4\u0026rdquo; schedule), 3) and another, non-rotating, schedule involving continuous 12 h daytime shifts during 40 days, with no work-free days in between (\u0026ldquo;fixed 12h\u0026rdquo; schedule). Our study employed objective measurements such as wrist-actigraphy to record sleep patterns, temperature loggers to monitor peripheral temperature rhythms, as well as subjective self-reports regarding fatigue, somnolence, and psycho-affective features. In all cases, the duration of sleep during the resting period was significantly less than the recommended 7 hours of nocturnal sleep. The \u0026ldquo;2x2x4\u0026rdquo;schedule resulted in decreased sleep regularity and increased circadian disruption, associated with more nocturnal sleep time after diurnal work. Also, this shift exhibited higher levels of insomnia, increased fatigue impact, lower alertness levels, and heightened symptoms of depression. Our findings indicate that specific parameters vary depending on the type of schedule worked suggesting that, in practical terms, certain schedules are healthier and safer for these workers. These results provide valuable insights for the design of safer and healthier work schedules, with the potential to enhance worker well-being and overall productivity.\u003c/p\u003e","manuscriptTitle":"Bridging the gap: examining circadian biology and fatigue alongside work schedules","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-05-10 20:18:55","doi":"10.21203/rs.3.rs-4345165/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-07-10T19:34:58+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-07-04T06:18:29+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-07-02T17:40:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"63811550694067180633421986020317000971","date":"2024-06-25T23:55:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"226160013770451599780038148761222114770","date":"2024-06-19T22:31:54+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-05-09T02:55:34+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-05-02T12:37:19+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-05-02T11:44:12+00:00","index":"","fulltext":""},{"type":"submitted","content":"npj Biological Timing and Sleep","date":"2024-04-29T22:04:03+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"npj-biological-timing-and-sleep","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [npj Biological Timing and Sleep](https://www.nature.com/npjbts)","snPcode":"44323","submissionUrl":"https://submission.springernature.com/new-submission/44323/3","title":"npj Biological Timing and Sleep","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6104f43a-3622-4b98-b47a-56ea5ed8b3ab","owner":[],"postedDate":"May 10th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":31621355,"name":"Biological sciences/Neuroscience/Circadian rhythms and sleep/Circadian regulation"},{"id":31621356,"name":"Biological sciences/Neuroscience/Circadian rhythms and sleep/Sleep deprivation"}],"tags":[],"updatedAt":"2024-09-06T14:56:03+00:00","versionOfRecord":[],"versionCreatedAt":"2024-05-10 20:18:55","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4345165","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4345165","identity":"rs-4345165","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}