Feasibility and Effects of High-Intensity Interval Training in Older Adults with Mild to Moderate Depressive Symptoms: A Pilot Cluster-Randomized Controlled Trial

Feasibility and Effects of High-Intensity Interval Training in Older Adults with Mild to Moderate Depressive Symptoms: A Pilot Cluster-Randomized Controlled Trial | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Feasibility and Effects of High-Intensity Interval Training in Older Adults with Mild to Moderate Depressive Symptoms: A Pilot Cluster-Randomized Controlled Trial Yanping Duan, Yanping Wang, Wei Liang, Heung-Sang Wong, Julien Steven Baker, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4160308/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background and aims: Older adults with mild-to-moderate depressive symptoms (MMDS) are at high risk to develop severe depression along with mortality and disability. The aim of this study was to investigate the feasibility and effects of high intensity interval training (HIIT) in older adults with MMDS. Methods Three elderly centers involving 24 older adults with MMDS were randomized into: 1) HIIT (n = 8); 2) moderate-intensity continuous training (Baduanjin Qigong) (MICT-BDJ) (n = 8); or 3) recreation workshop (RW) control (n = 8) for a 16-week (32 session) intervention. Feasibility was assessed using retention rate, session attendance rate, exercise intensity adherence, acceptability, and safety. Self-reported depressive symptoms and objectively measured physical fitness (PF) were assessed at baseline and post-intervention. Results 20 participants completed data collection twice. The retention rate was 87.5% (7/8), 87.5% (7/8), 75% (6/8) for HIIT, MICT-BDJ, and RW, respectively. 87.5% (7/8) of HIIT participants completed at least 75% of exercise sessions. 81.4% of HIIT participants achieved the pre-designed intensity (≥ 80% maximum heart rate) during the high-intensity intervals. All HIIT (7/7) participants were satisfied with their group allocation. More HIIT (6/7) than MICT-BDJ (5/7) participants found the exercise enjoyable. Two mild adverse events were reported in the HIIT group. HIIT improved depressive symptoms more than MICT-BDJ ( d = - 1.02) and RW ( d = - 1.32). Both HIIT ( d = 1.26) and MICT-BDJ ( d = 1.39) improved PF more than RW. Conclusion HIIT was feasible and effective in improving the depressive symptoms and PF for older adults with MMD. Trial registration: This study was registered on the ClinicalTrials Registry (NCT06014294). Preventive Medicine High-intensity interval training Baduanjin Qigong Exercise intervention depressive symptoms physical fitness feasibility Figures Figure 1 1. Introduction Depression is a common mental health problem among older adults, which is associated with physical impairment, psychiatric comorbidities and an elevated risk of morbidity and mortality (Wei et al., 2019 ). Previous studies have indicated approximately 30% prevalence of depressive symptoms among Hong Kong older adults (Cheung & Chou, 2019 ). A recent study revealed an aggravation of depressive symptoms among this vulnerable population during the COVID-19 pandemic in Hong Kong (Jin et al., 2022 ). Therefore, improving depression among Hong Kong older adults is a public health and economic imperative. Depending on the number and severity of symptoms, depression can be categorized as mild, moderate, and severe (NCD, 2012). Compared to people with mild and moderate depression, those with severe depression may develop psychotic symptoms (e.g., delusions) and have higher mortality and disability (NCD, 2012). Effective treatment for mild and moderate depressive symptoms can prevent the deterioration of depressive pathology to severe and psychotic symptoms and this is particularly important for older adults. Considerable evidence has demonstrated that regular physical exercise is associated with a lower prevalence of late-life depression (Catalan-Matamoros et al., 2016 ). Traditional moderate-intensity continuous training (MICT) (e.g., Baduanjin Qigong) has historically been the compelling exercise recommendation in the improvement of depression and physical fitness among older adults (Chang et al., 2019 ; Zou et al., 2017 ). However, older adults with mental illness have shown lower engagement and compliance with MICT programs compared to matched healthy controls due to potential lack of motivation and/or pleasure (ACSM, 2014). In recent years, high-intensity interval training (HIIT) has gained popularity as a novel, time-efficient, yet enjoyable exercise regimen that may overcome motivational barriers associated with traditional MICT (ACSM, 2014; Martland et al., 2020 ). HIIT is a form of exercise which includes repeated bouts of high-intensity exercise, typically lasting seconds to minutes, interspersed with periods of rest (ACSM, 2014; Martland et al., 2020 ). Just like traditional MICT, HIIT can involve many different forms of exercise from walking to dancing. The difference is that HIIT consists of alternating short bursts of high-intensity exercise (duration from 10s to 5min) that typically reach ≥ 80% individual maximum heart rate (HR max ), with recovery periods of rest/light exercise (duration ≤ 5min) at ≤ 70% HR max (Korman et al., 2020 ). A typical HIIT session can be up to three times shorter than a MICT session (ACSM, 2014; Korman et al., 2020 ; Martland et al., 2020 ). Previous evidence has indicated that HIIT interventions demonstrated superior performance outcomes in improving brain-derived growth neurotrophins, dopamine, and other chemicals compared to MICT, suggesting biological advantages of HIIT interventions for depression prevention and treatment compared to traditional MICT (Fiorelli et al., 2019 ; O’Callaghan et al., 2020). Most importantly, HIIT has shown advantages in terms of more time-efficiency, more enjoyment, as well as higher engagement and adherence of participants relative to MICT programs among adults with mental illness (ACSM, 2014; Korman et al., 2020 ; Martland et al., 2020 ). Recently, Keating et al. reviewed 15 articles comparing the application of HIIT and MICT in older adults who were healthy sedentary, or people with heart disease and type-2 diabetes (Keating et al., 2020 ). All studies expressed a comparable or superior effect of HIIT on cardiorespiratory fitness measures. Additionally, Marriott et al. reviewed 69 studies of HIIT application in older adults (Marriott et al., 2021 ). Most studies focused on healthy older adults (n = 30), followed by individuals with physical illness (e.g., cardiovascular; n = 29) and other clinical diseases (e.g., Alzheimer’s diseases; n = 10). The review findings showed that HIIT programs were generally well-tolerated and may provide many health benefits for older adults when compared to control groups. To date, no study examined the feasibility and effects of HIIT in older adults with depressive symptoms. Additionally, most existing HIIT studies have shown several methodological weaknesses, such as a lack of methods of randomization and blinding, as well as inadequate control groups (Korman et al., 2020 ). Further, most HIIT programs have been conducted in lab-settings using cycle ergometer or treadmills. This may limit the application of HIIT interventions when generalizing to real-world settings (e.g., at home environments or elderly centers). Given the above, the aims of this pilot study were (1) to evaluate the feasibility of HIIT for older adults with mild to moderate depressive symptoms and (2) to examine the effects of a HIIT intervention on depressive symptoms and physical fitness in older adults compared to a MICT-Baduanjin Qigong intervention and a control group. 2. Methods This study comprised a single-blinded, three-group, 16-week cluster-randomized controlled trial (C-RCT) with baseline and post-intervention outcome measures. Participants were Hong Kong community-dwelling older adults with mild to moderate depressive symptoms. The study protocol was approved by the Research Ethics Committee of Hong Kong Baptist University (REC/21–22/0169) and was registered on the ClinicalTrials Registry (NCT06014294). Data were collected between April 2023 and August 2023. 2.1 Participants Participant recruitment and randomization were implemented at the cluster level, where neighborhood elderly centers were randomly recruited over a 2-month period from the three major districts of Hong Kong (Hong Kong Island, Kowloon, New Territories), China. Eligible elderly centers fulfilled the criterion that there were no ongoing projects related to physical exercise promotion that might contaminate the effects estimate of this study. Eligible centers were randomized into three groups: HIIT, MICT-Baduanjin Qigong (MICT-BDJ) exercise, or non-exercise control (recreation workshop). Randomization was undertaken using the random function in Excel, with a ratio of 1:1:1, by a research team member who was not involved in the intervention implementation, data collection, and outcome evaluation. Both intervention facilitators and data assessors were blinded to the group allocation. All older adults in the recruited elderly centers were invited to participate in the study, where eligible participants met the inclusion criteria: 1) aged 60–74; 2) have mild or moderate depressive symptoms (i.e., scoring 5–11 in the Chinese version of Geriatric Depression Scale, GDS-C) (Cheng & Chan, 2006); 3) pass the Physical Activity Readiness Questionnaire plus (PAR-Q+) screening or with the physician’s approval for the readiness of participation in the high-intensity exercise; 4) no restriction on physical mobility; 5) no cognitive impairment (i.e., scoring < 24 in the Chinese version of the Mini-Mental Status Examination. MMSE-C) (Tse et al., 2013 ); and 6) no previous profound experiences with practicing HIIT or Baduanjin Qigong. For the sample size estimate, according to the rule of thumb for pilot studies, a minimum of three elderly centers with total 18 participants (6 participants per center) are required to ensure adequate information for assessing feasibility and effectiveness (Thabane et al., 2010 ; Toohey et al., 2020 ).Considering an attrition rate of around 25% (MacDonald et al., 2021 ) and around 30% prevalence of depression symptoms among Hong Kong older adults (Cheung & Chou, 2019 ), at least 81 participants (27 participants per center) should be contacted at the initial recruitment stage. The flow of eligible participants through the study is shown in Fig. 1. All participants completed the written informed consent form before study commenced. 2.2 Intervention contents The two exercise groups (HIIT and MICT-BDJ) received a 16-week exercise training program, comprising of 2 sessions per week (a total of 32 training sessions). Each session comprised three sections, including warm-up, main exercise, and cool down. For the HIIT group, the intensity was designed in consideration of the safety and maximum benefit for older adults based on the recommendations of the American College of Sports Medicine (ACSM) (Heath, 2005). Intensity was monitored using heart rate monitors (Polar Verity Sense) and the self-reported Rate of Perceived Exertion (RPE) (Borg Category Ratio 10 Scale) (Knapen et al., 2003 ). For Week 1–2, the HIIT section included 10 intervals of 30s HIIT work at 80–90% HR max (5–8 RPE), separated by 9 intervals of 60s active recovery at 60–70% HR max (2–3 RPE). For the warm-up and cool-down sections, the intensity was set as 50%-70% HR max (1–3 RPE). The workloads of each HIIT interval were increased by 5s every two weeks and finally reached 65s in Week 15–16. The total HIIT section progressed from 14 min in Weeks 1–2 to 19 min 50s in Weeks 15–16. Each HIIT section consisted of ten distinct movements (cardiorespiratory exercise + resistance training), where one movement was repeated as many times as possible based on the individuals’ physical fitness and their intraday health status within one work interval. For instance, the first 30s work interval in Week 1–2 included maximum repeated bouts of the first movement (lunge with fast punch). In addition, to avoid participants finding the exercise boring, four movements were updated in the HIIT protocol every two weeks. As a result, there were in total 38 movements in the movement bank of HIIT work. The content for the HIIT program is outlined in Appendix 1, Table S1. The HIIT session was guided by a qualified HIIT instructor with the assistance of student helpers. Following the safe, supportive, active, and enjoyable principles (Eather et al., 2020 ), a series of strategies were employed in the HIIT group, including 1) the HIIT sessions were performed in different small teams of maximum 4 participants in one team with similar physical fitness and maximum heart rate; 2) participants in each small team wore Polar Verity Sense heart rate monitors connected to the Polar Go-Fit iPad TM application, which was monitored by a student helper and displayed on a screen for participants to view during exercise sessions; 3) participants were asked to report their overall RPE of HIIT work intervals after the completion of all HIIT sections; 4) all exercise sessions were performed with continuous music and the music tempo was set as 120–140 bpm for HIIT sections, and 60–80 bpm for warm-up and cool-down sections. One week before conducting the formal HIIT program, a preparation session was implemented at the research lab. With the assistance of student helpers, participants in the HIIT group were estimated for their maximum heart rate values using a formula, which has been applied previously for elderly populations [HRmax = 208 – (0.7 × age)] (Tanaka et al., 2001 ). Participants were then familiarized with the whole HIIT procedure as well as the 38 movements. Finally, participants were asked to implement a trial of HIIT section designed for week 1–2, where they were required to adjust their movement speed to reach the required HIIT intensity. For the MICT group, Baduanjin Qigong exercise was utilized. This is in consideration that 1) the feasibility and effects of Baduanjin Qigong on improving older adults’ depressive symptoms have been demonstrated by previous studies (Chang et al., 2019 ; Zou et al., 2017 ); and 2) as a type of MICT, Baduanjin Qigong demonstrates a prominent distinction to the HIIT. The 16-week MICT-BDJ comprised four phases: cognitive phase, associated phase, automatic phase (with guidance), and automatic phase (without guidance), adjusted from the three stages of motor learning by Fitts and Posner (1967). The entire set of MICT-BDJ included 10 postures, which has been confirmed feasible and safe for older adults by the Chinese Health Qigong Association ( https://www.sport.gov.cn/qgzx/n5407/c781297/content.html ). The intensity of MICT-BDJ section was set as 60–70% HR max (2–3 RPE). The content for the MICT-BDJ program is outlined in Appendix 1, Table S2. A qualified Baduanjin instructor guided the MICT-BDJ group. The same training principles of individuality and progression as well as the strategies used in the HIIT group (e.g., one student helper assist maxi. 4 participants, with music, reporting overall RPE) were also applied to MICT-BDJ group. To control the influence of confounders (e.g., social aspects of group activities) and to avoid the expectation/Hawthorne effect, participants in the non-exercise control group received a series of group-based workshops related to daily recreation that were identical in all respects to the HIIIT and MICT-BDJ groups (e.g., frequency and duration of intervention). The workshops were delivered by a research assistant and conducted in the elderly community center. It covered four topics throughout the 16 weeks (see Appendix 1, Table S3), and each workshop included both instructor-delivered knowledge session and group-interaction session (e.g., Q&A, group discussion, sharing among participants). 2.3 Measurement Feasibility was assessed using five indicators which includes 1) retention rate (% of participants completing assessments at the baseline and at the end of the intervention). Criterion: more than 70% of participants completed data collection (Chapman et al., 2017 ; MacDonald et al., 2021 ); 2) session attendance rate. Criterion: at least 2/3 (66.7%) of participants completed at least 75% of intervention sessions (24/32 sessions) (MacDonald et al., 2021 ; Tew et al., 2019 ); 3) exercise intensity adherence. Criteria: at least 80% of participant's average %HR max during the high-intensity intervals reached ≥ 80%HR max in the HIIT group (Tew et al., 2019 ); and the overall RPEs of HIIT and MICT-BDJ cross all exercise sessions fall into 5–8 points and 2–3 points respectively referring to the exercise protocol. 4) acceptability of the exercise condition was assessed at post-intervention using a 10-item self-reported scale (Chapman et al., 2017 ) in HIIT and MICT-BDJ participants. Responses were given on a 5-point Likert scale (strongly disagree, disagree, neutral, agree, and strongly agree) (Cronbach’s alpha = 0.89). Questionnaire items are presented in Table 1. and 5) exercise safety. The number and type of study-related adverse events or cases were reported during the 16-week exercise sessions. Depressive symptoms were assessed using the Chinese version of the 15-item Geriatric Depression Scale (GDS-C) (Cheng & Chan, 2006) (Cronbach’s α = 0.83). Answers are given on a yes/no scale. The total score ranges from 0 to 15, with a higher score indicating a severer level of depressive symptoms, in particular, 0–4 = normal, 5–8 = mild depression, 9–11 = moderate depression and 12–15 = severe depression. Physical fitness was assessed using the Senior Fitness Test (SFT) (Rikli & Jones, 2013 ). SFT consisted of seven testing items measuring all the five dimensions of physical fitness, including body mass index (BMI), 30s chair stand for lower limbs’ muscle strength, 30s arm curl for upper limbs’ muscle strength, 2-min step test for aerobic endurance, chair sit-and-reach test for lower body flexibility, back scratch test for upper body flexibility, and 8ft up-and-go test for agility and dynamic balance. The reliability and validity of the testing items have been previously described in the SFT Manual (Rikli & Jones, 2013 ). 2.4 Data analysis Data analyses were conducted using SPSS 28.0. Mean, standard deviation (SD), frequency, and percentage (%) were used to present the descriptive characteristics of participants and five indicators of feasibility of intervention. Independent t-test were employed for evaluating the difference between HIIT and MICT-BDJ participants in the exercise intensity (RPE). Responses to the acceptability questionnaire were regrouped into three categories (disagree, neutral, agree) to generate summary statistics. These were then regrouped into two categories (disagree/neutral, agree) for evaluating the difference between HIIT and MICT-BDJ participants in acceptability items by using Chi-square Pearson tests. Generalized linear mixed models were applied for evaluating the intervention effects on depressive symptoms and physical fitness, with time, groups, and their interaction as fixed effects, with a random intercept fitted for subjects. The significance level was set as p < 0.05 (two-tailed) and the effect size Cohen’s d was calculated for within and between groups, where d = 0.20, 0.50, 0.80 indicating a small, medium, and large effect size, respectively. 3. Results The baseline characteristics of participants are outlined in Table 2. In terms of the feasibility, for retention rate, the total retention rate was 83.3% (20/24), with 87.5% (7/8) for HIIT, 87.5% (7/8) for MICT-BDJ, and 75% (6/8) for recreation workshop, respectively, which achieved the pre-defined retention rate of 70%. For session attendance, only participants who attend at least one intervention session were included in the analysis (HIIT = 8, MICT-BDJ = 8, recreation workshop = 7). The total session attendance rate was 88.3% ± 0.082 (range: 71.9%-96.9%), with 86.6% ± 0.059, 88% ± 0.109, 90.6% ± 0.077 for HIIT, MICT-BDJ, and recreation workshop, respectively. The median (IQR) number of sessions attended was 28 ± 3 (range: 25.5–28.5), 28.5 ± 7.5 (range: 23.5–31), and 27.5 ± 5 (range: 26–31) for HIIT, MICT-BDJ, and recreation workshop, respectively. 87.5% (7/8) of the HIIT participants, 75% (6/8) of the MICT-BDJ participants, and 85.7% (6/7) of the workshop participants completed at least 75% of intervention sessions (24/32 sessions). For exercise intensity adherence, it was monitored by using heart rate (HR) and RPE. For HIIT group, the average HR increased from 120 bpm to 128 bpm through the progression of training, and the average peak HR ranged from 140 bpm to 151 bpm. The average % HR max was 78.4% (± 0.01, 75–81%) during HIIT section including workout and recovery. 81.4% of participants’ average %HR max reached ≥ 80%HR max during the high-intensity intervals (range: 66.67%-100%), while 18.6% of participants performed below target intensity in some sessions (as shown in Appendix 2, Figure S1). In addition, both HIIT and MICT-BDJ reported overall RPE at the end of each session to show intensity adherence. As shown in Appendix 2, Figure S2, participants in the HIIT group exercising at higher intensities [mean (standard deviation), RPE = 7.66 (0.82); range: 6.14–9] compared to those in the MICT-BDJ group [RPE = 2.83 (0.47); range: 2–3.67]. The significantly higher RPE ( t 62 = 28.96, p < 0.001) was reported in HIIT group compared to MICT-BDJ group cross all exercise sessions. For acceptability, as shown in Table 1, 14 participants (HIIT = 7, MICT-BDJ = 7) who received at least one exercise session and completed post-intervention assessment were involved in the acceptability analyses. It was indicated that 100% (7/7) of HIIT participants were satisfied with their group allocations compared to 71.4% (5/7) of MICT-BDJ participants showing their satisfaction. More HIIT than MICT-BDJ participants found the exercise enjoyable (HIIT 85.7%, MICT-BDJ 71.4%). No participants reported that the exercise was boring or too hard both in HIIT and MICT-BDJ. All HIIT participants (100%, 7/7) looked forward to the exercise sessions while 85.7% (6/7) for MICT-BDJ participants. Chi-square tests did not show any significant differences between conditions for any of the acceptability items ( p = 0.127). For exercise safety, we documented two mild study-related adverse events in the HIIT group while no adverse events were reported in MICT-BDJ group. These adverse events were knee soreness (n = 1) and low back pain (n = 1) and were resolved within the duration of the study. In terms of intervention efficacy, there were significant time × group interaction effects for depressive symptoms ( F 2,17 = 3.7, p = 0.046), where participants in the HIIT group prominently alleviated their depressive symptoms with a large effect size compared to MICT-BDJ ( d = -1.02) and workshop control group ( d = -1.32). A significant time × group interaction effect was also found for the z-score of total physical fitness ( F 2,17 = 4.5, p = 0.026). Both HIIT and MICT-BDJ showed favorable improvements in total physical fitness compared to the workshop control group with large effect sizes ( d = 1.26–1.39). For the subdomains of physical fitness, significant time × group interactions were observed for chair sit-and-reach ( F 2,17 = 3.7, p = 0.048) and back scratch testing ( F 2,17 = 5.3, p = 0.016). Both HIIT and MICT-BDJ showed favorable improvements in chair sit-and-reach and back scratch compared to the workshop control group with large effect sizes ( d chair sit−and−reach = 1.01–1.3, d back scratch = 1.29–1.53). There was no significant time × group interaction effect for BMI, 30s arm curl, and 8ft up-and-go ( p > .05). However, both HIIT and MICT-BDJ had large effect sizes for BMI (| d | = 0.97–1.01) and moderate to large effect sizes for 30s arm curl ( d = 0.73–1.01) in comparison to the workshop control group. In comparison to MICT-BDJ and the workshop control group, the HIIT group had large effect sizes for 8ft up-and-go (| d | = 0.84–1.17). More details can be found in Table 3. 4. Discussion This pilot C-RCT study, for the first time, to the best of our knowledge provides results on the feasibility and effects of high-intensity interval training in older adults with mild or moderate depressive symptoms for the first time to our knowledge. We found that the HIIT was well tolerated with retention rates and session attendance rates that were superior to or comparable to MICT-BDJ and recreation workshop. The HIIT group achieved the pre-defined exercise intensity adherence rate with mild adverse events. All HIIT participants were satisfied with the exercise and most of them found the exercise enjoyable. Additionally, the HIIT group showed a superior improvement in depressive symptoms compared to MICT-BDJ and recreation workshop groups. Both exercise groups indicated a favorable enhancement in physical fitness compared to the recreation workshop group. It is notable that the study retention of two exercise groups (87.5%) were higher than the recreation workshop group (75%), which is also higher than reported in previous exercise training program among adults with mental illness (82%) (Chapman et al., 2017 ). 87.5% of the HIIT participants and 75% of the MICT-BDJ participants completed at least 75% of exercise sessions in this study, which was satisfactory and higher than those reported in previous HIIT studies with older adults with various medical conditions (e.g., major depression, breast cancer, HIV) (Chapman et al., 2017 ; Schulz et al., 2018 ). Compared to previous HIIT programs that recommended a 1:1 or 1:2 ratio for high-intensity workload and recovery (Schulz et al., 2018 ), this study implemented a progressively increasing setting that ranged from a 1:2 ratio (with 30s of exertion and 60s of active recovery for Week 1–2) to an approximately 1:1 ratio (with 65s of exertion and 60s of active recovery for Week 15–16). 81.4% of participants in the HIIT group were able to achieve the pre-defined exercise intensity as monitored by objective measurements, thereby supporting the feasibility of the progressive HIIT protocol employed in this study. Previous lab-based HIIT programs commonly employ machines (e.g., cycle ergometer, treadmill) due to the ease of monitoring exercise intensity (Pires Peixoto et al., 2020 ). However, implementing this type of exercise in a real-world context that targets a larger sample size of populations can be challenging. Additionally, exercises performed using machines are limited in their ability to fully develop the essential skills of balance, gait and coordination that are vital to the daily lives of older adults (Galloza et al., 2017 ). In addition, for older adults with mental illness, group-based exercise has been extensively recommended in previous studies (Stevens et al., 2021 ). Therefore, the exercise protocol employed in this study is tailored to meet the needs of older adults with mild or moderate depressive symptoms at a real-world setting, incorporating a group-based, machine-free exercise format, supervised multifaceted exercise movements, ample social support, and musical accompaniment. Overall, this pilot study provided evidence supporting the satisfaction, enjoyment, and safety of the HIIT program. In terms of the intervention effects, this study revealed the superiority of the HIIT on alleviating depressive symptoms in older adults with mild to moderate depression compared to MICT-BDJ and recreation workshop control groups, which is in line with Dunn et al’s study finding targeting adults diagnosed with mild to moderate major depressive disorder (Dunn et al., 2005 ). It implies that HIIT can be an alternative exercise regimen in improving depressive symptoms among elderly participants. This study also showed the comparable effects of HIIT and MICT-BDJ on physical fitness, which supports previous empirical studies and meta-analyses in older adults who were healthy sedentary, or people with heart disease and type-2 diabetes (Marriott et al., 2021 ; Wu et al., 2021 ). This study has several notable strengths, including a rigorous double-blinded C-RCT design, the incorporation of a recreation workshop control to mitigate potential psychosocial confounders, as well as machine-free and easy operation movements of HIIT program. However, the limitations of this study include its small sample size and the narrow demographic profile of the participants (over 70% were female), male individuals may yield different results. Moreover, the exercise intensity of MICT-BDJ was monitored using self-reported RPE, which may produce recall bias. Future studies should include objective measures (e.g., heart rate monitors) and compare the exercise intensity adherence with %HRmax achieved between HIIT and MICT-BDJ. Furthermore, depressive symptoms were assessed using a self-reported scale. While the scale has been extensively validated in previous studies with older adults, the measure biases (e.g., recall-bias, social expectation) cannot be eliminated. More objective measures (e.g., biomarkers) should be added in the future studies. Additionally, the underlying biological and psychosocial mechanisms that contribute to the successful reduction of depressive symptoms warrant further investigation. In summary, this pilot study provides evidence for the feasibility of the HIIT program as well as its efficacy in ameliorating depressive symptoms and enhancing physical fitness in community-dwelling older adults with mild to moderate depression. Large-scale trails are required to affirm these findings and to identify potential mechanisms to enable evidence-based exercise recommendations for this population in the future. Declarations CRediT authorship contribution statement Conceptualization, Y.D. and W.L.; methodology, Y.D., W.L., Y.W., H.W. S.Y. and J.S.B.; validation, Y.D., W.L. and Y.W.; formal analysis, W.L. and Y.W.; investigation, Y.D. and Y.W.; resources, Y.D ; data curation, W.Y. and W.L.; writing—original draft preparation, Y.D., W.L. and W.Y.; writing—review and editing, H.W., S.Y. and J.S.B.; supervision, Y.D.; project administration, Y.D.; funding acquisition, Y.D. All authors have read and agreed to the published version of the manuscript. Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Funding This research was funded by the General Research Fund of Hong Kong (Ref. No. 12616922; 2022/23). The study protocol was approved by the Research Ethics Committee of Hong Kong Baptist University (REC/21–22/0169) and was registered on the ClinicalTrials Registry (NCT06014294). Informed consent was obtained from all subjects involved in the study. Acknowledgments We would like to express our gratitude to the Research Grants Council of Hong Kong who provided us the financial support as well as to the elderly community centers who provided generous assistance in participant recruitment and data collection. Data Availability The datasets generated during the present study are not publicly available, owing to the risk of disclosure or deduction of private individual information, but they are available from the corresponding author on reasonable request. References American College of Sports Medicine. Information on High-Intensity Interval Training . 2014. [5 Aug 2023]. Available from: https://www.acsm.org/docs/default-source/files-for-resource-library/high-intensity-interval-training.pdf Catalan-Matamoros D, Gomez-Conesa A, Stubbs B, Vancampfort D. (2016). Exercise improves depressive symptoms in older adults: An umbrella review of systematic reviews and meta-analyses. Psychiatry Res. 244:202-209. doi:10.1016/j.psychres.2016.07.028 Chang PS, Knobf T, Oh B, Funk M. (2019). Physical and Psychological Health Outcomes of Qigong Exercise in Older Adults: A Systematic Review and Meta-Analysis. Am J Chin Med. 47(2):301-322. doi:10.1142/S0192415X19500149 Chapman JJ, Coombes JS, Brown WJ et al. (2017). The feasibility and acceptability of high-intensity interval training for adults with mental illness: A pilot study. Mental Health and Physical Activity . 13:40-48. https://doi.org/https://doi.org/10.1016/j.mhpa.2017.09.007 Cheng ST, Chan AC. (2004). A brief version of the geriatric depression scale for the Chinese [published correction appears in Psychol Assess. 2006 Mar;18(1):48]. Psychol Assess. 16(2):182-186. doi:10.1037/1040-3590.16.2.182 Cheung KCK, Chou KL. (2019). Poverty, deprivation, and depressive symptoms among older adults in Hong Kong. Aging Ment Health . 23(1):22-29. doi:10.1080/13607863.2017.1394438 Dunn AL, Trivedi MH, Kampert JB, Clark CG, Chambliss HO. (2005). Exercise treatment for depression: efficacy and dose response. Am J Prev Med. 28(1):1-8. doi:10.1016/j.amepre.2004.09.003. PMID: 15626549. Eather N, Babic M, Riley N, et al. (2020). Integrating high-intensity interval training into the workplace: The Work-HIIT pilot RCT. Scand J Med Sci Sports . 30(12):2445-2455. doi:10.1111/sms.13811 Fiorelli CM, Ciolac EG, Simieli L, et al. (2019). Differential acute effect of high-intensity interval or continuous moderate exercise on cognition in individuals with Parkinson's Disease. J Phys Act Health. 16(2):157-164. doi:10.1123/jpah.2018-0189 Galloza J, Castillo B, Micheo W. (2017). Benefits of Exercise in the Older Population. Phys Med Rehabil Clin N Am . 28(4):659-669. doi:10.1016/j.pmr.2017.06.001 Heath, Edward H. ACSM’s Guidelines for Exercise Testing and Prescription, 7th Edition. Medicine & Science in Sports & Exercise 37(11):p 2018, November 2005. doi: 10.1249/01.mss.0000189073.33400.04 Jin Y, Sun HL, Lam SC, et al. (2022). Depressive symptoms and gender differences in older adults in Hong Kong during the COVID-19 pandemic: a network analysis approach. Int J Biol Sci. 18(10):3934-3941. doi:10.7150/ijbs.69460 Keating CJ, Párraga Montilla JÁ, Latorre Román PÁ, Moreno Del Castillo R. (2020). Comparison of high-intensity interval training to moderate-intensity continuous training in older adults: a systematic review. J Aging Phys Act . 1-10. doi:10.1123/japa.2019-0111 Korman N, Armour M, Chapman J, et al. (2020). High Intensity Interval training (HIIT) for people with severe mental illness: A systematic review & meta-analysis of intervention studies- considering diverse approaches for mental and physical recovery. Psychiatry Res. 284:112601. doi:10.1016/j.psychres.2019.112601 Knapen J, Van de V, P., Van C, H PJ, & Pieters G. (2003). Evaluation of cardio-respiratory fitness and perceived exertion for patients with depressive and anxiety disorders: a study on reliability. Disability and Rehabilitation . 25(23): 1312-1315 MacDonald G, Sitlinger A, Deal MA, et al. (2021). A pilot study of high-intensity interval training in older adults with treatment naïve chronic lymphocytic leukemia. Sci Rep. 11(1):23137. doi:10.1038/s41598-021-02352-6 Marriott CFS, Petrella AFM, Marriott ECS, Boa Sorte Silva NC, Petrella RJ. (2021). High-intensity interval training in older adults: a scoping review. Sports Med Open . 7(1):49. doi:10.1186/s40798-021-00344-4 Martland R, Mondelli V, Gaughran F, Stubbs B. (2020). Can high intensity interval training improve health outcomes among people with mental illness? A systematic review and preliminary meta-analysis of intervention studies across a range of mental illnesses. J Affect Disord . 263:629-660. doi:10.1016/j.jad.2019.11.039 Non-Communicable Diseases Watch. Depression: Beyond Feeling Blue. 2012. [5 Aug 2023]. Available from https://www.chp.gov.hk/files/pdf/ncd_watch_sep2012.pdf O'Callaghan A, Harvey M, Houghton D, et al. (2020). Comparing the influence of exercise intensity on brain-derived neurotrophic factor serum levels in people with Parkinson's disease: a pilot study. Aging Clin Exp Res . 32(9):1731-1738. doi:10.1007/s40520-019-01353-w Pires Peixoto R, Trombert V, Poncet A, et al. (2020). Feasibility and safety of high-intensity interval training for the rehabilitation of geriatric inpatients (HIITERGY) a pilot randomized study. BMC Geriatr. 20(1):197. doi:10.1186/s12877-020-01596-7 Rikli RE, Jones CJ. (2013). Development and validation of criterion-referenced clinically relevant fitness standards for maintaining physical independence in later years. Gerontologist. 53(2):255-267. doi:10.1093/geront/gns071 Schulz SVW, Laszlo R, Otto S, et al. (2018). Feasibility and effects of a combined adjuvant high-intensity interval/strength training in breast cancer patients: a single-center pilot study. Disabil Rehabil . 40(13):1501-1508. doi:10.1080/09638288.2017.1300688 Stevens M, Lieschke J, Cruwys T, Cárdenas D, Platow MJ, Reynolds KJ. (2021). Better together: How group-based physical activity protects against depression. Soc Sci Med. 286:114337. Doi:10.1016/j.socscimed.2021.114337 Tanaka H, Monahan KD, Seals DR. (2001). Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 37(1):153-156. doi:10.1016/s0735-1097(00)01054-8 Tew GA, Leighton D, Carpenter R, et al. (2019). High-intensity interval training and moderate-intensity continuous training in adults with Crohn's disease: a pilot randomized controlled trial. BMC Gastroenterol . 19(1):19. doi:10.1186/s12876-019-0936-x Thabane L, Ma J, Chu R, et al. (2010). A tutorial on pilot studies: what, why and how. BMC Med Res Methodol. 10:1. doi:10.1186/1471-2288-10-1 Toohey K, Pumpa K, McKune A, et al. (2020). The impact of high-intensity interval training exercise on breast cancer survivors: a pilot study to explore fitness, cardiac regulation and biomarkers of the stress systems. BMC Cancer . 20(1):787. doi:10.1186/s12885-020-07295-1 Tse CS, Chang JF, Leung GT, et al. (2013). Effects of education on very mild dementia among Chinese people in Hong Kong: potential mediators in the Cantonese Mini-Mental State Examination tasks. Aging Ment Health . 17(3):310-318. doi:10.1080/13607863.2012.743962 Wei J, Hou R, Zhang X, et al. (2019). The association of late-life depression with all-cause and cardiovascular mortality among community-dwelling older adults: systematic review and meta-analysis. Br J Psychiatry. 215(2):449-455. doi:10.1192/bjp.2019.74 Wu ZJ, Wang ZY, Gao HE, Zhou XF, Li FH. (2021). Impact of high-intensity interval training on cardiorespiratory fitness, body composition, physical fitness, and metabolic parameters in older adults: A meta-analysis of randomized controlled trials. Exp Gerontol . 150:111345. doi:10.1016/j.exger.2021.111345 Zou L, SasaKi JE, Wang H, Xiao Z, Fang Q, Zhang M. (2017). A Systematic Review and Meta-Analysis Baduanjin Qigong for Health Benefits: Randomized Controlled Trials. Evid Based Complement Alternat Med . 2017:4548706. doi:10.1155/2017/454870 Tables Table 1 Acceptability of the exercise condition (n = 14) Questionnaire item Group Disagree n (%) Neutral n (%) Agree n (%) 1. I feel satisfied with the exercise condition that I was allocated to HIIT 0 (0%) 0 (0%) 7 (100%) MICT-BDJ 0 (0%) 2 (28.6%) 5 (71.4%) 2. I would have preferred to be in the other exercise condition HIIT 7 (100%) 0 (0%) 0 (0%) MICT-BDJ 7 (100%) 0 (0%) 0 (0%) 3. I found the exercise enjoyable HIIT 0 (0%) 1 (14.3%) 6 (85.7%) MICT-BDJ 0 (0%) 2 (28.6%) 5 (71.4%) 4. I found the exercise too hard HIIT 6 (85.7%) 1 (14.3%) 0 (0%) MICT-BDJ 6 (85.7%) 1 (14.3%) 0 (0%) 5. I found the exercise boring HIIT 7 (100%) 0 (0%) 0 (0%) MICT-BDJ 6 (85.7%) 1 (14.3%) 0 (0%) 6. I would have preferred group-based exercise HIIT 0 (0%) 2 (28.6%) 5 (71.4%) MICT-BDJ 0 (0%) 3 (42.9%) 4 (57.1%) 7. I looked forward to the exercise sessions HIIT 0 (0%) 0 (0%) 7 (100%) MICT-BDJ 0 (0%) 1 (14.3%) 6 (85.7%) 8. I would like to continue doing this kind of exercise outside of the study HIIT 1 (14.3%) 1 (14.3%) 5 (71.4%) MICT-BDJ 0 (0%) 0 (0%) 7 (100%) 9. I would feel confident doing this kind of exercise without assistance HIIT 0 (0%) 3 (42.9%) 4 (57.1%) MICT-BDJ 1 (14.3%) 2 (28.6%) 4 (57.1%) 10. I would feel confident being able to do this kind of exercise when having a bad day HIIT 1 (14.3%) 1 (14.3%) 5 (71.4%) MICT-BDJ 1 (14.3%) 2 (28.6%) 4 (57.1%) Note: HIIT: high-intensity interval training; MICT-BDJ: moderate-intensity continuous training-Baduanjin. Table 2 Baseline characteristics of the study sample by group allocation. Total (n = 20) HIIT (n = 7) MICT-BDJ (n = 7) RW (n = 6) Age, years, mean (SD) 69.9 (3.5) 70.1 (3.5) 68.3 (4.4) 71 (1.8) Female, n (%) 18 (90%) 5 (71.4%) 7 (100%) 6 (100%) Marital status, n (%) Single 5 (25%) 1 (14.3%) 2 (28.6%) 0 (0%) Married 11 (55%) 4 (57.1%) 4 (57.1%) 5 (83.3%) Divorced/widowed 4 (20%) 2 (28.6%) 1 (14.3%) 1 (16.7%) Education level, n (%) Primary or below 5 (25%) 2 (28.6%) 0 (0%) 3 (50%) Middle or high school 12 (60%) 3 (42.8%) 6 (85.7%) 3 (50%) College or above 3 (15%) 2 (28.6%) 1 (14.3%) 0 (0%) Occupational status Employed 1 (5%) 1 (14.3%) 0 (0%) 0 (0%) Unemployed/Retired 19 (95%) 6 (85.7%) 7 (100%) 6 (100%) Household income, n (%) <HK$20,000/month 18 (90%) 7 (100%) 5 (71.4%) 6 (100%) ≥HK$20,000/month 2 (10%) 0 (0%) 2 (28.6%) 0 (0%) BMI, kg/m 2 , mean (SD) 23.1 (2.7) 23.9 (2.5) 21 (2.4) 24.7 (1.5) Note. HIIT = high-intensity interval training; MICT-BDJ = moderate-intensity continuous training-Baduanjin; RW= recreation workshop; SD = standard deviation; BMI = body mass index. Table 3 Outcome data for depressive symptoms and physical fitness. Outcome measures HIIT MICT-BDJ RW Intervention effect HIIT vs RW HIIT vs MICT-BDJ Pre Post Pre Post Pre Post Time Group Time x group d d Depressive symptoms 6.4 (1.9) 3.3 (2.1) 6.9 (3.1) 5.7 (3.8) 6.8 (1.7) 6 (2.1) F 1,17 = 20.3 P < 0.001 F 2,17 = 0.8 P = 0.450 F 2,17 = 3.7 P = 0.046 - 1.32 - 1.02 Total PT z-score 0.2 (0.3) 0.3 (0.3) -0.3 (0.4) -0.1 (0.3) 0.1 (0.2) -0.3 (0.4) F 1,17 = 0.2 P = 0.627 F 2,17 = 4.4 P = 0.030 F 2,17 = 4.5 P = 0.026 1.26 -0.27 BMI (kg/m 2 ) 23.9 (2.5) 23.5 (2.3) 21 (2.4) 20.7 (2.1) 24.7 (1.5) 24.7 (1.5) F 1,17 = 3.4 P = 0.084 F 2,17 = 5.7 P = 0.012 F 2,17 = 1.8 P = 0.189 - 0.97 -0.03 30s chair stand 21.9 (6.5) 23.1 (6.8) 14.9 (9) 17.3 (5.3) 10.8 (5.5) 12.5 (6) F 1,17 = 4.8 P = 0.043 F 2,17 = 4.7 P = 0.023 F 2,17 = 0.2 P = 0.840 -0.15 -0.27 30s arm curl 21.7 (7.1) 24.4 (5.1) 14.3 (5.8) 16.7 (4.9) 14 (4.2) 13 (4.9) F 1,17 = 2.1 P = 0.167 F 2,17 = 6.8 P = 0.007 F 2,17 = 1.5 P = 0.255 1.01 0.07 2min step 83.1 (17.8) 103.6 (9.6) 71 (19.8) 94.1 (22.9) 55.8 (35.9) 63 (34.1) F 1,17 = 6.8 P = 0.018 F 2,17 = 5 P = 0.020 F 2,17 = 0.5 P = 0.590 0.46 -0.1 Chair sit-and-reach 6.9 (11.6) 10 (9.6) 13.6 (8.6) 13.9 (13.9) 11.6 (7.2) -0.1 (9.2) F 1,17 = 1.4 P = 0.252 F 2,17 = 1.4 P = 0.285 F 2,17 = 3.7 P = 0.048 1.3 0.38 Back scratch 5.1 (7.6) 5.4 (5) 6 (2.4) 6.9 (4.5) 11.4 (5.5) -0.8 (8.8) F 1,17 = 4.1 P = 0.060 F 2,17 = 0.2 P = 0.840 F 2,17 = 5.3 P = 0.016 1.29 -0.12 8ft up-and-go 5.8 (1.1) 5.3 (0.6) 5 (1.1) 5.4 (1) 6.6 (1) 6.7 (1.1) F 1,17 = 0.1 P = 0.936 F 2,17 = 4.5 P = 0.027 F 2,17 = 2 P = 0.162 - 0.84 - 1.17 Note. Pre and post are mean (SD); d = standardized change score expressed as Cohen’s d . Abbreviations: HIIT = high-intensity interval training; MICT-BDJ = moderate-intensity continuous training-Baduanjin; RW = recreation workshop; PT = physical fitness. Bold values signify moderate or large effect sizes. Additional Declarations The authors declare no competing interests. Supplementary Files Appendix1TableS1S3.docx Appendix 1-Table S1-S3 Appendix2FigureS1S2.docx Appendix 2-Figure S1-S2 Cite Share Download PDF Status: Posted Version 1 posted 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-4160308","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":283375689,"identity":"ba01ea10-5892-4e11-97a4-95d20a2b1020","order_by":0,"name":"Yanping Duan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1UlEQVRIiWNgGAWjYDCCA2DSJkFCAkSzMTAY8BCnJY10LYdJ0MJ3I/nZY94d5/MkZ/cYMHwoO8xgznMAvxbJG2nmxrxnbhdLy5wxYJxx7jCDZW8Dfi0GNxLMpHnbbifOk8gxYOZtO8xgcJ6AwwxupH8DajkH0fKXOC05IFsOJM4GaWEEaTlLwGGSZ96USc49k5w4c86xgoM959J5DM4cwK+F73j6Nom3O+wSZ9xu3vjgR5m1nMGZBAIuAwImXqhTQMYTjEgwYPzZQJS6UTAKRsEoGKkAAFYcSQY1DVIkAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-6432-7542","institution":"Hong Kong Baptist University","correspondingAuthor":true,"prefix":"","firstName":"Yanping","middleName":"","lastName":"Duan","suffix":""},{"id":283375690,"identity":"39c89ea1-9ac2-459a-9744-e3340312f888","order_by":1,"name":"Yanping Wang","email":"","orcid":"","institution":"Hong Kong Baptist 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University","correspondingAuthor":false,"prefix":"","firstName":"Julien","middleName":"Steven","lastName":"Baker","suffix":""},{"id":283375694,"identity":"845c3989-7025-408f-9fd7-b6efeade3faa","order_by":5,"name":"Shuyan Yang","email":"","orcid":"","institution":"City University of Macau","correspondingAuthor":false,"prefix":"","firstName":"Shuyan","middleName":"","lastName":"Yang","suffix":""}],"badges":[],"createdAt":"2024-03-25 03:05:46","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":true,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-4160308/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4160308/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":53508323,"identity":"15812f7e-a4c4-4348-bf46-2b93728ac4c1","added_by":"auto","created_at":"2024-03-26 20:52:26","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":217099,"visible":true,"origin":"","legend":"\u003cp\u003eCONSORT diagram depicting the flow of participants through the study\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4160308/v1/d4d067c9d673651fdc0b8439.jpg"},{"id":53508669,"identity":"0618a418-5625-4d58-91e6-6c26198d59ea","added_by":"auto","created_at":"2024-03-26 21:00:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":452942,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4160308/v1/c1d614ac-19d8-4d2d-9bd4-ad597d320826.pdf"},{"id":53508324,"identity":"237ef5e3-5f17-4d37-804e-e51f1e013c1b","added_by":"auto","created_at":"2024-03-26 20:52:26","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":24787,"visible":true,"origin":"","legend":"\u003cp\u003eAppendix 1-Table S1-S3\u003c/p\u003e","description":"","filename":"Appendix1TableS1S3.docx","url":"https://assets-eu.researchsquare.com/files/rs-4160308/v1/36d293fd9236252bd8788ec2.docx"},{"id":53508325,"identity":"c4622c12-50a6-4cc7-bb6f-25b03ad7bb55","added_by":"auto","created_at":"2024-03-26 20:52:26","extension":"docx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":278829,"visible":true,"origin":"","legend":"\u003cp\u003eAppendix 2-Figure S1-S2\u003c/p\u003e","description":"","filename":"Appendix2FigureS1S2.docx","url":"https://assets-eu.researchsquare.com/files/rs-4160308/v1/b6fc94c4ca7664cc7101f25f.docx"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eFeasibility and Effects of High-Intensity Interval Training in Older Adults with Mild to Moderate Depressive Symptoms: A Pilot Cluster-Randomized Controlled Trial\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eDepression is a common mental health problem among older adults, which is associated with physical impairment, psychiatric comorbidities and an elevated risk of morbidity and mortality (Wei et al., \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Previous studies have indicated approximately 30% prevalence of depressive symptoms among Hong Kong older adults (Cheung \u0026amp; Chou, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). A recent study revealed an aggravation of depressive symptoms among this vulnerable population during the COVID-19 pandemic in Hong Kong (Jin et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Therefore, improving depression among Hong Kong older adults is a public health and economic imperative.\u003c/p\u003e \u003cp\u003eDepending on the number and severity of symptoms, depression can be categorized as mild, moderate, and severe (NCD, 2012). Compared to people with mild and moderate depression, those with severe depression may develop psychotic symptoms (e.g., delusions) and have higher mortality and disability (NCD, 2012). Effective treatment for mild and moderate depressive symptoms can prevent the deterioration of depressive pathology to severe and psychotic symptoms and this is particularly important for older adults.\u003c/p\u003e \u003cp\u003eConsiderable evidence has demonstrated that regular physical exercise is associated with a lower prevalence of late-life depression (Catalan-Matamoros et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Traditional moderate-intensity continuous training (MICT) (e.g., Baduanjin Qigong) has historically been the compelling exercise recommendation in the improvement of depression and physical fitness among older adults (Chang et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Zou et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). However, older adults with mental illness have shown lower engagement and compliance with MICT programs compared to matched healthy controls due to potential lack of motivation and/or pleasure (ACSM, 2014). In recent years, high-intensity interval training (HIIT) has gained popularity as a novel, time-efficient, yet enjoyable exercise regimen that may overcome motivational barriers associated with traditional MICT (ACSM, 2014; Martland et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHIIT is a form of exercise which includes repeated bouts of high-intensity exercise, typically lasting seconds to minutes, interspersed with periods of rest (ACSM, 2014; Martland et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Just like traditional MICT, HIIT can involve many different forms of exercise from walking to dancing. The difference is that HIIT consists of alternating short bursts of high-intensity exercise (duration from 10s to 5min) that typically reach\u0026thinsp;\u0026ge;\u0026thinsp;80% individual maximum heart rate (HR\u003csub\u003emax\u003c/sub\u003e), with recovery periods of rest/light exercise (duration\u0026thinsp;\u0026le;\u0026thinsp;5min) at \u0026le;\u0026thinsp;70% HR\u003csub\u003emax\u003c/sub\u003e (Korman et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). A typical HIIT session can be up to three times shorter than a MICT session (ACSM, 2014; Korman et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Martland et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Previous evidence has indicated that HIIT interventions demonstrated superior performance outcomes in improving brain-derived growth neurotrophins, dopamine, and other chemicals compared to MICT, suggesting biological advantages of HIIT interventions for depression prevention and treatment compared to traditional MICT (Fiorelli et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; O\u0026rsquo;Callaghan et al., 2020). Most importantly, HIIT has shown advantages in terms of more time-efficiency, more enjoyment, as well as higher engagement and adherence of participants relative to MICT programs among adults with mental illness (ACSM, 2014; Korman et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Martland et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eRecently, Keating et al. reviewed 15 articles comparing the application of HIIT and MICT in older adults who were healthy sedentary, or people with heart disease and type-2 diabetes (Keating et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). All studies expressed a comparable or superior effect of HIIT on cardiorespiratory fitness measures. Additionally, Marriott et al. reviewed 69 studies of HIIT application in older adults (Marriott et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Most studies focused on healthy older adults (n\u0026thinsp;=\u0026thinsp;30), followed by individuals with physical illness (e.g., cardiovascular; n\u0026thinsp;=\u0026thinsp;29) and other clinical diseases (e.g., Alzheimer\u0026rsquo;s diseases; n\u0026thinsp;=\u0026thinsp;10). The review findings showed that HIIT programs were generally well-tolerated and may provide many health benefits for older adults when compared to control groups. To date, no study examined the feasibility and effects of HIIT in older adults with depressive symptoms. Additionally, most existing HIIT studies have shown several methodological weaknesses, such as a lack of methods of randomization and blinding, as well as inadequate control groups (Korman et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Further, most HIIT programs have been conducted in lab-settings using cycle ergometer or treadmills. This may limit the application of HIIT interventions when generalizing to real-world settings (e.g., at home environments or elderly centers).\u003c/p\u003e \u003cp\u003eGiven the above, the aims of this pilot study were (1) to evaluate the feasibility of HIIT for older adults with mild to moderate depressive symptoms and (2) to examine the effects of a HIIT intervention on depressive symptoms and physical fitness in older adults compared to a MICT-Baduanjin Qigong intervention and a control group.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cp\u003eThis study comprised a single-blinded, three-group, 16-week cluster-randomized controlled trial (C-RCT) with baseline and post-intervention outcome measures. Participants were Hong Kong community-dwelling older adults with mild to moderate depressive symptoms. The study protocol was approved by the Research Ethics Committee of Hong Kong Baptist University (REC/21\u0026ndash;22/0169) and was registered on the ClinicalTrials Registry (NCT06014294). Data were collected between April 2023 and August 2023.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Participants\u003c/h2\u003e \u003cp\u003eParticipant recruitment and randomization were implemented at the cluster level, where neighborhood elderly centers were randomly recruited over a 2-month period from the three major districts of Hong Kong (Hong Kong Island, Kowloon, New Territories), China. Eligible elderly centers fulfilled the criterion that there were no ongoing projects related to physical exercise promotion that might contaminate the effects estimate of this study. Eligible centers were randomized into three groups: HIIT, MICT-Baduanjin Qigong (MICT-BDJ) exercise, or non-exercise control (recreation workshop). Randomization was undertaken using the random function in Excel, with a ratio of 1:1:1, by a research team member who was not involved in the intervention implementation, data collection, and outcome evaluation. Both intervention facilitators and data assessors were blinded to the group allocation.\u003c/p\u003e \u003cp\u003eAll older adults in the recruited elderly centers were invited to participate in the study, where eligible participants met the inclusion criteria: 1) aged 60\u0026ndash;74; 2) have mild or moderate depressive symptoms (i.e., scoring 5\u0026ndash;11 in the Chinese version of Geriatric Depression Scale, GDS-C) (Cheng \u0026amp; Chan, 2006); 3) pass the Physical Activity Readiness Questionnaire plus (PAR-Q+) screening or with the physician\u0026rsquo;s approval for the readiness of participation in the high-intensity exercise; 4) no restriction on physical mobility; 5) no cognitive impairment (i.e., scoring\u0026thinsp;\u0026lt;\u0026thinsp;24 in the Chinese version of the Mini-Mental Status Examination. MMSE-C) (Tse et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2013\u003c/span\u003e); and 6) no previous profound experiences with practicing HIIT or Baduanjin Qigong.\u003c/p\u003e \u003cp\u003eFor the sample size estimate, according to the rule of thumb for pilot studies, a minimum of three elderly centers with total 18 participants (6 participants per center) are required to ensure adequate information for assessing feasibility and effectiveness (Thabane et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Toohey et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).Considering an attrition rate of around 25% (MacDonald et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2021\u003c/span\u003e) and around 30% prevalence of depression symptoms among Hong Kong older adults (Cheung \u0026amp; Chou, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), at least 81 participants (27 participants per center) should be contacted at the initial recruitment stage. The flow of eligible participants through the study is shown in Fig.\u0026nbsp;1. All participants completed the written informed consent form before study commenced.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Intervention contents\u003c/h2\u003e \u003cp\u003eThe two exercise groups (HIIT and MICT-BDJ) received a 16-week exercise training program, comprising of 2 sessions per week (a total of 32 training sessions). Each session comprised three sections, including warm-up, main exercise, and cool down. For the HIIT group, the intensity was designed in consideration of the safety and maximum benefit for older adults based on the recommendations of the American College of Sports Medicine (ACSM) (Heath, 2005). Intensity was monitored using heart rate monitors (Polar Verity Sense) and the self-reported Rate of Perceived Exertion (RPE) (Borg Category Ratio 10 Scale) (Knapen et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). For Week 1\u0026ndash;2, the HIIT section included 10 intervals of 30s HIIT work at 80\u0026ndash;90% HR\u003csub\u003emax\u003c/sub\u003e (5\u0026ndash;8 RPE), separated by 9 intervals of 60s active recovery at 60\u0026ndash;70% HR\u003csub\u003emax\u003c/sub\u003e (2\u0026ndash;3 RPE). For the warm-up and cool-down sections, the intensity was set as 50%-70% HR\u003csub\u003emax\u003c/sub\u003e (1\u0026ndash;3 RPE). The workloads of each HIIT interval were increased by 5s every two weeks and finally reached 65s in Week 15\u0026ndash;16. The total HIIT section progressed from 14 min in Weeks 1\u0026ndash;2 to 19 min 50s in Weeks 15\u0026ndash;16. Each HIIT section consisted of ten distinct movements (cardiorespiratory exercise\u0026thinsp;+\u0026thinsp;resistance training), where one movement was repeated as many times as possible based on the individuals\u0026rsquo; physical fitness and their intraday health status within one work interval. For instance, the first 30s work interval in Week 1\u0026ndash;2 included maximum repeated bouts of the first movement (lunge with fast punch). In addition, to avoid participants finding the exercise boring, four movements were updated in the HIIT protocol every two weeks. As a result, there were in total 38 movements in the movement bank of HIIT work. The content for the HIIT program is outlined in Appendix 1, Table S1. The HIIT session was guided by a qualified HIIT instructor with the assistance of student helpers.\u003c/p\u003e \u003cp\u003eFollowing the safe, supportive, active, and enjoyable principles (Eather et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), a series of strategies were employed in the HIIT group, including 1) the HIIT sessions were performed in different small teams of maximum 4 participants in one team with similar physical fitness and maximum heart rate; 2) participants in each small team wore Polar Verity Sense heart rate monitors connected to the Polar Go-Fit iPad \u003csup\u003eTM\u003c/sup\u003e application, which was monitored by a student helper and displayed on a screen for participants to view during exercise sessions; 3) participants were asked to report their overall RPE of HIIT work intervals after the completion of all HIIT sections; 4) all exercise sessions were performed with continuous music and the music tempo was set as 120\u0026ndash;140 bpm for HIIT sections, and 60\u0026ndash;80 bpm for warm-up and cool-down sections.\u003c/p\u003e \u003cp\u003eOne week before conducting the formal HIIT program, a preparation session was implemented at the research lab. With the assistance of student helpers, participants in the HIIT group were estimated for their maximum heart rate values using a formula, which has been applied previously for elderly populations [HRmax\u0026thinsp;=\u0026thinsp;208 \u0026ndash; (0.7 \u0026times; age)] (Tanaka et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Participants were then familiarized with the whole HIIT procedure as well as the 38 movements. Finally, participants were asked to implement a trial of HIIT section designed for week 1\u0026ndash;2, where they were required to adjust their movement speed to reach the required HIIT intensity.\u003c/p\u003e \u003cp\u003eFor the MICT group, Baduanjin Qigong exercise was utilized. This is in consideration that 1) the feasibility and effects of Baduanjin Qigong on improving older adults\u0026rsquo; depressive symptoms have been demonstrated by previous studies (Chang et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Zou et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2017\u003c/span\u003e); and 2) as a type of MICT, Baduanjin Qigong demonstrates a prominent distinction to the HIIT. The 16-week MICT-BDJ comprised four phases: cognitive phase, associated phase, automatic phase (with guidance), and automatic phase (without guidance), adjusted from the three stages of motor learning by Fitts and Posner (1967). The entire set of MICT-BDJ included 10 postures, which has been confirmed feasible and safe for older adults by the Chinese Health Qigong Association (\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.sport.gov.cn/qgzx/n5407/c781297/content.html\u003c/span\u003e\u003cspan address=\"https://www.sport.gov.cn/qgzx/n5407/c781297/content.html\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e). The intensity of MICT-BDJ section was set as 60\u0026ndash;70% HR\u003csub\u003emax\u003c/sub\u003e (2\u0026ndash;3 RPE). The content for the MICT-BDJ program is outlined in Appendix 1, Table S2. A qualified Baduanjin instructor guided the MICT-BDJ group. The same training principles of individuality and progression as well as the strategies used in the HIIT group (e.g., one student helper assist maxi. 4 participants, with music, reporting overall RPE) were also applied to MICT-BDJ group.\u003c/p\u003e \u003cp\u003eTo control the influence of confounders (e.g., social aspects of group activities) and to avoid the expectation/Hawthorne effect, participants in the non-exercise control group received a series of group-based workshops related to daily recreation that were identical in all respects to the HIIIT and MICT-BDJ groups (e.g., frequency and duration of intervention). The workshops were delivered by a research assistant and conducted in the elderly community center. It covered four topics throughout the 16 weeks (see Appendix 1, Table S3), and each workshop included both instructor-delivered knowledge session and group-interaction session (e.g., Q\u0026amp;A, group discussion, sharing among participants).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Measurement\u003c/h2\u003e \u003cp\u003eFeasibility was assessed using five indicators which includes 1) retention rate (% of participants completing assessments at the baseline and at the end of the intervention). Criterion: more than 70% of participants completed data collection (Chapman et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; MacDonald et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2021\u003c/span\u003e); 2) session attendance rate. Criterion: at least 2/3 (66.7%) of participants completed at least 75% of intervention sessions (24/32 sessions) (MacDonald et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Tew et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2019\u003c/span\u003e); 3) exercise intensity adherence. Criteria: at least 80% of participant's average %HR max during the high-intensity intervals reached\u0026thinsp;\u0026ge;\u0026thinsp;80%HR max in the HIIT group (Tew et al., \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2019\u003c/span\u003e); and the overall RPEs of HIIT and MICT-BDJ cross all exercise sessions fall into 5\u0026ndash;8 points and 2\u0026ndash;3 points respectively referring to the exercise protocol. 4) acceptability of the exercise condition was assessed at post-intervention using a 10-item self-reported scale (Chapman et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) in HIIT and MICT-BDJ participants. Responses were given on a 5-point Likert scale (strongly disagree, disagree, neutral, agree, and strongly agree) (Cronbach\u0026rsquo;s alpha\u0026thinsp;=\u0026thinsp;0.89). Questionnaire items are presented in Table\u0026nbsp;1. and 5) exercise safety. The number and type of study-related adverse events or cases were reported during the 16-week exercise sessions.\u003c/p\u003e \u003cp\u003eDepressive symptoms were assessed using the Chinese version of the 15-item Geriatric Depression Scale (GDS-C) (Cheng \u0026amp; Chan, 2006) (Cronbach\u0026rsquo;s α\u0026thinsp;=\u0026thinsp;0.83). Answers are given on a yes/no scale. The total score ranges from 0 to 15, with a higher score indicating a severer level of depressive symptoms, in particular, 0\u0026ndash;4\u0026thinsp;=\u0026thinsp;normal, 5\u0026ndash;8\u0026thinsp;=\u0026thinsp;mild depression, 9\u0026ndash;11\u0026thinsp;=\u0026thinsp;moderate depression and 12\u0026ndash;15\u0026thinsp;=\u0026thinsp;severe depression.\u003c/p\u003e \u003cp\u003ePhysical fitness was assessed using the Senior Fitness Test (SFT) (Rikli \u0026amp; Jones, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). SFT consisted of seven testing items measuring all the five dimensions of physical fitness, including body mass index (BMI), 30s chair stand for lower limbs\u0026rsquo; muscle strength, 30s arm curl for upper limbs\u0026rsquo; muscle strength, 2-min step test for aerobic endurance, chair sit-and-reach test for lower body flexibility, back scratch test for upper body flexibility, and 8ft up-and-go test for agility and dynamic balance. The reliability and validity of the testing items have been previously described in the SFT Manual (Rikli \u0026amp; Jones, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2013\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Data analysis\u003c/h2\u003e \u003cp\u003eData analyses were conducted using SPSS 28.0. Mean, standard deviation (SD), frequency, and percentage (%) were used to present the descriptive characteristics of participants and five indicators of feasibility of intervention. Independent t-test were employed for evaluating the difference between HIIT and MICT-BDJ participants in the exercise intensity (RPE). Responses to the acceptability questionnaire were regrouped into three categories (disagree, neutral, agree) to generate summary statistics. These were then regrouped into two categories (disagree/neutral, agree) for evaluating the difference between HIIT and MICT-BDJ participants in acceptability items by using Chi-square Pearson tests. Generalized linear mixed models were applied for evaluating the intervention effects on depressive symptoms and physical fitness, with time, groups, and their interaction as fixed effects, with a random intercept fitted for subjects. The significance level was set as \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 (two-tailed) and the effect size Cohen\u0026rsquo;s \u003cem\u003ed\u003c/em\u003e was calculated for within and between groups, where \u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.20, 0.50, 0.80 indicating a small, medium, and large effect size, respectively.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003eThe baseline characteristics of participants are outlined in Table\u0026nbsp;2. In terms of the feasibility, for retention rate, the total retention rate was 83.3% (20/24), with 87.5% (7/8) for HIIT, 87.5% (7/8) for MICT-BDJ, and 75% (6/8) for recreation workshop, respectively, which achieved the pre-defined retention rate of 70%. For session attendance, only participants who attend at least one intervention session were included in the analysis (HIIT\u0026thinsp;=\u0026thinsp;8, MICT-BDJ\u0026thinsp;=\u0026thinsp;8, recreation workshop\u0026thinsp;=\u0026thinsp;7). The total session attendance rate was 88.3% \u0026plusmn; 0.082 (range: 71.9%-96.9%), with 86.6% \u0026plusmn; 0.059, 88% \u0026plusmn; 0.109, 90.6% \u0026plusmn; 0.077 for HIIT, MICT-BDJ, and recreation workshop, respectively. The median (IQR) number of sessions attended was 28\u0026thinsp;\u0026plusmn;\u0026thinsp;3 (range: 25.5\u0026ndash;28.5), 28.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.5 (range: 23.5\u0026ndash;31), and 27.5\u0026thinsp;\u0026plusmn;\u0026thinsp;5 (range: 26\u0026ndash;31) for HIIT, MICT-BDJ, and recreation workshop, respectively. 87.5% (7/8) of the HIIT participants, 75% (6/8) of the MICT-BDJ participants, and 85.7% (6/7) of the workshop participants completed at least 75% of intervention sessions (24/32 sessions). For exercise intensity adherence, it was monitored by using heart rate (HR) and RPE. For HIIT group, the average HR increased from 120 bpm to 128 bpm through the progression of training, and the average peak HR ranged from 140 bpm to 151 bpm. The average % HR max was 78.4% (\u0026plusmn;\u0026thinsp;0.01, 75\u0026ndash;81%) during HIIT section including workout and recovery. 81.4% of participants\u0026rsquo; average %HR max reached\u0026thinsp;\u0026ge;\u0026thinsp;80%HR max during the high-intensity intervals (range: 66.67%-100%), while 18.6% of participants performed below target intensity in some sessions (as shown in Appendix 2, Figure S1). In addition, both HIIT and MICT-BDJ reported overall RPE at the end of each session to show intensity adherence. As shown in Appendix 2, Figure S2, participants in the HIIT group exercising at higher intensities [mean (standard deviation), RPE\u0026thinsp;=\u0026thinsp;7.66 (0.82); range: 6.14\u0026ndash;9] compared to those in the MICT-BDJ group [RPE\u0026thinsp;=\u0026thinsp;2.83 (0.47); range: 2\u0026ndash;3.67]. The significantly higher RPE (\u003cem\u003et\u003c/em\u003e\u003csub\u003e62\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;28.96, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) was reported in HIIT group compared to MICT-BDJ group cross all exercise sessions.\u003c/p\u003e \u003cp\u003eFor acceptability, as shown in Table\u0026nbsp;1, 14 participants (HIIT\u0026thinsp;=\u0026thinsp;7, MICT-BDJ\u0026thinsp;=\u0026thinsp;7) who received at least one exercise session and completed post-intervention assessment were involved in the acceptability analyses. It was indicated that 100% (7/7) of HIIT participants were satisfied with their group allocations compared to 71.4% (5/7) of MICT-BDJ participants showing their satisfaction. More HIIT than MICT-BDJ participants found the exercise enjoyable (HIIT 85.7%, MICT-BDJ 71.4%). No participants reported that the exercise was boring or too hard both in HIIT and MICT-BDJ. All HIIT participants (100%, 7/7) looked forward to the exercise sessions while 85.7% (6/7) for MICT-BDJ participants. Chi-square tests did not show any significant differences between conditions for any of the acceptability items (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.127).\u003c/p\u003e \u003cp\u003eFor exercise safety, we documented two mild study-related adverse events in the HIIT group while no adverse events were reported in MICT-BDJ group. These adverse events were knee soreness (n\u0026thinsp;=\u0026thinsp;1) and low back pain (n\u0026thinsp;=\u0026thinsp;1) and were resolved within the duration of the study.\u003c/p\u003e \u003cp\u003eIn terms of intervention efficacy, there were significant time \u0026times; group interaction effects for depressive symptoms (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e2,17\u003c/sub\u003e = 3.7, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.046), where participants in the HIIT group prominently alleviated their depressive symptoms with a large effect size compared to MICT-BDJ (\u003cem\u003ed\u003c/em\u003e = -1.02) and workshop control group (\u003cem\u003ed\u003c/em\u003e = -1.32). A significant time \u0026times; group interaction effect was also found for the z-score of total physical fitness (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e2,17\u003c/sub\u003e = 4.5, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.026). Both HIIT and MICT-BDJ showed favorable improvements in total physical fitness compared to the workshop control group with large effect sizes (\u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.26\u0026ndash;1.39). For the subdomains of physical fitness, significant time \u0026times; group interactions were observed for chair sit-and-reach (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e2,17\u003c/sub\u003e = 3.7, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.048) and back scratch testing (\u003cem\u003eF\u003c/em\u003e\u003csub\u003e2,17\u003c/sub\u003e = 5.3, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.016). Both HIIT and MICT-BDJ showed favorable improvements in chair sit-and-reach and back scratch compared to the workshop control group with large effect sizes (\u003cem\u003ed\u003c/em\u003e \u003csub\u003e\u003cem\u003echair sit\u0026minus;and\u0026minus;reach\u003c/em\u003e\u003c/sub\u003e = 1.01\u0026ndash;1.3, \u003cem\u003ed\u003c/em\u003e \u003csub\u003e\u003cem\u003eback scratch\u003c/em\u003e\u003c/sub\u003e = 1.29\u0026ndash;1.53). There was no significant time \u0026times; group interaction effect for BMI, 30s arm curl, and 8ft up-and-go (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;.05). However, both HIIT and MICT-BDJ had large effect sizes for BMI (|\u003cem\u003ed\u003c/em\u003e| = 0.97\u0026ndash;1.01) and moderate to large effect sizes for 30s arm curl (\u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.73\u0026ndash;1.01) in comparison to the workshop control group. In comparison to MICT-BDJ and the workshop control group, the HIIT group had large effect sizes for 8ft up-and-go (|\u003cem\u003ed\u003c/em\u003e| = 0.84\u0026ndash;1.17). More details can be found in Table\u0026nbsp;3.\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis pilot C-RCT study, for the first time, to the best of our knowledge provides results on the feasibility and effects of high-intensity interval training in older adults with mild or moderate depressive symptoms for the first time to our knowledge. We found that the HIIT was well tolerated with retention rates and session attendance rates that were superior to or comparable to MICT-BDJ and recreation workshop. The HIIT group achieved the pre-defined exercise intensity adherence rate with mild adverse events. All HIIT participants were satisfied with the exercise and most of them found the exercise enjoyable. Additionally, the HIIT group showed a superior improvement in depressive symptoms compared to MICT-BDJ and recreation workshop groups. Both exercise groups indicated a favorable enhancement in physical fitness compared to the recreation workshop group.\u003c/p\u003e \u003cp\u003eIt is notable that the study retention of two exercise groups (87.5%) were higher than the recreation workshop group (75%), which is also higher than reported in previous exercise training program among adults with mental illness (82%) (Chapman et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). 87.5% of the HIIT participants and 75% of the MICT-BDJ participants completed at least 75% of exercise sessions in this study, which was satisfactory and higher than those reported in previous HIIT studies with older adults with various medical conditions (e.g., major depression, breast cancer, HIV) (Chapman et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Schulz et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eCompared to previous HIIT programs that recommended a 1:1 or 1:2 ratio for high-intensity workload and recovery (Schulz et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), this study implemented a progressively increasing setting that ranged from a 1:2 ratio (with 30s of exertion and 60s of active recovery for Week 1\u0026ndash;2) to an approximately 1:1 ratio (with 65s of exertion and 60s of active recovery for Week 15\u0026ndash;16). 81.4% of participants in the HIIT group were able to achieve the pre-defined exercise intensity as monitored by objective measurements, thereby supporting the feasibility of the progressive HIIT protocol employed in this study.\u003c/p\u003e \u003cp\u003ePrevious lab-based HIIT programs commonly employ machines (e.g., cycle ergometer, treadmill) due to the ease of monitoring exercise intensity (Pires Peixoto et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). However, implementing this type of exercise in a real-world context that targets a larger sample size of populations can be challenging. Additionally, exercises performed using machines are limited in their ability to fully develop the essential skills of balance, gait and coordination that are vital to the daily lives of older adults (Galloza et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). In addition, for older adults with mental illness, group-based exercise has been extensively recommended in previous studies (Stevens et al., \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Therefore, the exercise protocol employed in this study is tailored to meet the needs of older adults with mild or moderate depressive symptoms at a real-world setting, incorporating a group-based, machine-free exercise format, supervised multifaceted exercise movements, ample social support, and musical accompaniment. Overall, this pilot study provided evidence supporting the satisfaction, enjoyment, and safety of the HIIT program.\u003c/p\u003e \u003cp\u003eIn terms of the intervention effects, this study revealed the superiority of the HIIT on alleviating depressive symptoms in older adults with mild to moderate depression compared to MICT-BDJ and recreation workshop control groups, which is in line with Dunn et al\u0026rsquo;s study finding targeting adults diagnosed with mild to moderate major depressive disorder (Dunn et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). It implies that HIIT can be an alternative exercise regimen in improving depressive symptoms among elderly participants. This study also showed the comparable effects of HIIT and MICT-BDJ on physical fitness, which supports previous empirical studies and meta-analyses in older adults who were healthy sedentary, or people with heart disease and type-2 diabetes (Marriott et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Wu et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThis study has several notable strengths, including a rigorous double-blinded C-RCT design, the incorporation of a recreation workshop control to mitigate potential psychosocial confounders, as well as machine-free and easy operation movements of HIIT program. However, the limitations of this study include its small sample size and the narrow demographic profile of the participants (over 70% were female), male individuals may yield different results. Moreover, the exercise intensity of MICT-BDJ was monitored using self-reported RPE, which may produce recall bias. Future studies should include objective measures (e.g., heart rate monitors) and compare the exercise intensity adherence with %HRmax achieved between HIIT and MICT-BDJ. Furthermore, depressive symptoms were assessed using a self-reported scale. While the scale has been extensively validated in previous studies with older adults, the measure biases (e.g., recall-bias, social expectation) cannot be eliminated. More objective measures (e.g., biomarkers) should be added in the future studies. Additionally, the underlying biological and psychosocial mechanisms that contribute to the successful reduction of depressive symptoms warrant further investigation.\u003c/p\u003e \u003cp\u003eIn summary, this pilot study provides evidence for the feasibility of the HIIT program as well as its efficacy in ameliorating depressive symptoms and enhancing physical fitness in community-dwelling older adults with mild to moderate depression. Large-scale trails are required to affirm these findings and to identify potential mechanisms to enable evidence-based exercise recommendations for this population in the future.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCRediT authorship contribution statement\u003c/h2\u003e \u003cp\u003eConceptualization, Y.D. and W.L.; methodology, Y.D., W.L., Y.W., H.W. S.Y. and J.S.B.; validation, Y.D., W.L. and Y.W.; formal analysis, W.L. and Y.W.; investigation, Y.D. and Y.W.; resources, Y.D ; data curation, W.Y. and W.L.; writing\u0026mdash;original draft preparation, Y.D., W.L. and W.Y.; writing\u0026mdash;review and editing, H.W., S.Y. and J.S.B.; supervision, Y.D.; project administration, Y.D.; funding acquisition, Y.D. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eDeclaration of competing interest\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis research was funded by the General Research Fund of Hong Kong (Ref. No. 12616922; 2022/23). The study protocol was approved by the Research Ethics Committee of Hong Kong Baptist University (REC/21\u0026ndash;22/0169) and was registered on the ClinicalTrials Registry (NCT06014294). Informed consent was obtained from all subjects involved in the study.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eWe would like to express our gratitude to the Research Grants Council of Hong Kong who provided us the financial support as well as to the elderly community centers who provided generous assistance in participant recruitment and data collection.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e \u003cp\u003eThe datasets generated during the present study are not publicly available, owing to the risk of disclosure or deduction of private individual information, but they are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAmerican College of Sports Medicine. \u003cem\u003eInformation on High-Intensity Interval Training\u003c/em\u003e. 2014. [5 Aug 2023]. Available from: https://www.acsm.org/docs/default-source/files-for-resource-library/high-intensity-interval-training.pdf\u003c/li\u003e\n\u003cli\u003eCatalan-Matamoros D, Gomez-Conesa A, Stubbs B, Vancampfort D. (2016). Exercise improves depressive symptoms in older adults: An umbrella review of systematic reviews and meta-analyses. \u003cem\u003ePsychiatry Res.\u003c/em\u003e 244:202-209. doi:10.1016/j.psychres.2016.07.028\u003c/li\u003e\n\u003cli\u003eChang PS, Knobf T, Oh B, Funk M. (2019). Physical and Psychological Health Outcomes of Qigong Exercise in Older Adults: A Systematic Review and Meta-Analysis. \u003cem\u003eAm J Chin Med.\u003c/em\u003e 47(2):301-322. doi:10.1142/S0192415X19500149\u003c/li\u003e\n\u003cli\u003eChapman JJ, Coombes JS, Brown WJ et al. (2017). The feasibility and acceptability of high-intensity interval training for adults with mental illness: A pilot study. \u003cem\u003eMental Health and Physical Activity\u003c/em\u003e. 13:40-48. https://doi.org/https://doi.org/10.1016/j.mhpa.2017.09.007\u003c/li\u003e\n\u003cli\u003eCheng ST, Chan AC. (2004). A brief version of the geriatric depression scale for the Chinese [published correction appears in Psychol Assess. 2006 Mar;18(1):48]. \u003cem\u003ePsychol Assess.\u003c/em\u003e 16(2):182-186. doi:10.1037/1040-3590.16.2.182\u003c/li\u003e\n\u003cli\u003eCheung KCK, Chou KL. (2019). Poverty, deprivation, and depressive symptoms among older adults in Hong Kong. \u003cem\u003eAging Ment Health\u003c/em\u003e. 23(1):22-29. doi:10.1080/13607863.2017.1394438\u003c/li\u003e\n\u003cli\u003eDunn AL, Trivedi MH, Kampert JB, Clark CG, Chambliss HO. (2005). Exercise treatment for depression: efficacy and dose response. \u003cem\u003eAm J Prev Med.\u003c/em\u003e 28(1):1-8. doi:10.1016/j.amepre.2004.09.003. PMID: 15626549.\u003c/li\u003e\n\u003cli\u003eEather N, Babic M, Riley N, et al. (2020). Integrating high-intensity interval training into the workplace: The Work-HIIT pilot RCT. \u003cem\u003eScand J Med Sci Sports\u003c/em\u003e. 30(12):2445-2455. doi:10.1111/sms.13811\u003c/li\u003e\n\u003cli\u003eFiorelli CM, Ciolac EG, Simieli L, et al. (2019). Differential acute effect of high-intensity interval or continuous moderate exercise on cognition in individuals with Parkinson\u0026apos;s Disease. \u003cem\u003eJ Phys Act Health.\u003c/em\u003e 16(2):157-164. doi:10.1123/jpah.2018-0189\u003c/li\u003e\n\u003cli\u003eGalloza J, Castillo B, Micheo W. (2017). Benefits of Exercise in the Older Population. \u003cem\u003ePhys Med Rehabil Clin N Am\u003c/em\u003e. 28(4):659-669. doi:10.1016/j.pmr.2017.06.001\u003c/li\u003e\n\u003cli\u003eHeath, Edward H. ACSM\u0026rsquo;s Guidelines for Exercise Testing and Prescription, 7th Edition. Medicine \u0026amp; Science in Sports \u0026amp; Exercise 37(11):p 2018, November 2005. doi: 10.1249/01.mss.0000189073.33400.04\u003c/li\u003e\n\u003cli\u003eJin Y, Sun HL, Lam SC, et al. (2022). Depressive symptoms and gender differences in older adults in Hong Kong during the COVID-19 pandemic: a network analysis approach. \u003cem\u003eInt J Biol Sci.\u003c/em\u003e 18(10):3934-3941. doi:10.7150/ijbs.69460\u003c/li\u003e\n\u003cli\u003eKeating CJ, P\u0026aacute;rraga Montilla J\u0026Aacute;, Latorre Rom\u0026aacute;n P\u0026Aacute;, Moreno Del Castillo R. (2020). Comparison of high-intensity interval training to moderate-intensity continuous training in older adults: a systematic review. \u003cem\u003eJ Aging Phys Act\u003c/em\u003e. 1-10. doi:10.1123/japa.2019-0111\u003c/li\u003e\n\u003cli\u003eKorman N, Armour M, Chapman J, et al. (2020). High Intensity Interval training (HIIT) for people with severe mental illness: A systematic review \u0026amp; meta-analysis of intervention studies- considering diverse approaches for mental and physical recovery. \u003cem\u003ePsychiatry Res.\u003c/em\u003e 284:112601. doi:10.1016/j.psychres.2019.112601\u003c/li\u003e\n\u003cli\u003eKnapen J, Van de V, P., Van C, H PJ, \u0026amp; Pieters G. (2003). Evaluation of cardio-respiratory fitness and perceived exertion for patients with depressive and anxiety disorders: a study on reliability. \u003cem\u003eDisability and Rehabilitation\u003c/em\u003e. 25(23): 1312-1315\u003c/li\u003e\n\u003cli\u003eMacDonald G, Sitlinger A, Deal MA, et al. (2021). A pilot study of high-intensity interval training in older adults with treatment na\u0026iuml;ve chronic lymphocytic leukemia. \u003cem\u003eSci Rep.\u003c/em\u003e 11(1):23137. doi:10.1038/s41598-021-02352-6\u003c/li\u003e\n\u003cli\u003eMarriott CFS, Petrella AFM, Marriott ECS, Boa Sorte Silva NC, Petrella RJ. (2021). High-intensity interval training in older adults: a scoping review. \u003cem\u003eSports Med Open\u003c/em\u003e. 7(1):49. doi:10.1186/s40798-021-00344-4\u003c/li\u003e\n\u003cli\u003eMartland R, Mondelli V, Gaughran F, Stubbs B. (2020). Can high intensity interval training improve health outcomes among people with mental illness? A systematic review and preliminary meta-analysis of intervention studies across a range of mental illnesses. \u003cem\u003eJ Affect Disord\u003c/em\u003e. 263:629-660. doi:10.1016/j.jad.2019.11.039\u003c/li\u003e\n\u003cli\u003eNon-Communicable Diseases Watch. Depression: Beyond Feeling Blue. 2012. [5 Aug 2023]. Available from https://www.chp.gov.hk/files/pdf/ncd_watch_sep2012.pdf\u003c/li\u003e\n\u003cli\u003eO\u0026apos;Callaghan A, Harvey M, Houghton D, et al. (2020). Comparing the influence of exercise intensity on brain-derived neurotrophic factor serum levels in people with Parkinson\u0026apos;s disease: a pilot study. \u003cem\u003eAging Clin Exp Res\u003c/em\u003e. 32(9):1731-1738. doi:10.1007/s40520-019-01353-w\u003c/li\u003e\n\u003cli\u003ePires Peixoto R, Trombert V, Poncet A, et al. (2020). Feasibility and safety of high-intensity interval training for the rehabilitation of geriatric inpatients (HIITERGY) a pilot randomized study. \u003cem\u003eBMC Geriatr.\u003c/em\u003e 20(1):197. doi:10.1186/s12877-020-01596-7\u003c/li\u003e\n\u003cli\u003eRikli RE, Jones CJ. (2013). Development and validation of criterion-referenced clinically relevant fitness standards for maintaining physical independence in later years. \u003cem\u003eGerontologist.\u003c/em\u003e 53(2):255-267. doi:10.1093/geront/gns071\u003c/li\u003e\n\u003cli\u003eSchulz SVW, Laszlo R, Otto S, et al. (2018). Feasibility and effects of a combined adjuvant high-intensity interval/strength training in breast cancer patients: a single-center pilot study. \u003cem\u003eDisabil Rehabil\u003c/em\u003e. 40(13):1501-1508. doi:10.1080/09638288.2017.1300688\u003c/li\u003e\n\u003cli\u003eStevens M, Lieschke J, Cruwys T, C\u0026aacute;rdenas D, Platow MJ, Reynolds KJ. (2021). Better together: How group-based physical activity protects against depression. \u003cem\u003eSoc Sci Med.\u003c/em\u003e 286:114337. Doi:10.1016/j.socscimed.2021.114337\u003c/li\u003e\n\u003cli\u003eTanaka H, Monahan KD, Seals DR. (2001). Age-predicted maximal heart rate revisited. \u003cem\u003eJ Am Coll Cardiol. \u003c/em\u003e37(1):153-156. doi:10.1016/s0735-1097(00)01054-8\u003c/li\u003e\n\u003cli\u003eTew GA, Leighton D, Carpenter R, et al. (2019). High-intensity interval training and moderate-intensity continuous training in adults with Crohn\u0026apos;s disease: a pilot randomized controlled trial. \u003cem\u003eBMC Gastroenterol\u003c/em\u003e. 19(1):19. doi:10.1186/s12876-019-0936-x\u003c/li\u003e\n\u003cli\u003eThabane L, Ma J, Chu R, et al. (2010). A tutorial on pilot studies: what, why and how. \u003cem\u003eBMC Med Res Methodol. \u003c/em\u003e10:1. doi:10.1186/1471-2288-10-1\u003c/li\u003e\n\u003cli\u003eToohey K, Pumpa K, McKune A, et al. (2020). The impact of high-intensity interval training exercise on breast cancer survivors: a pilot study to explore fitness, cardiac regulation and biomarkers of the stress systems. \u003cem\u003eBMC Cancer\u003c/em\u003e. 20(1):787. doi:10.1186/s12885-020-07295-1\u003c/li\u003e\n\u003cli\u003eTse CS, Chang JF, Leung GT, et al. (2013). Effects of education on very mild dementia among Chinese people in Hong Kong: potential mediators in the Cantonese Mini-Mental State Examination tasks. \u003cem\u003eAging Ment Health\u003c/em\u003e. 17(3):310-318. doi:10.1080/13607863.2012.743962\u003c/li\u003e\n\u003cli\u003eWei J, Hou R, Zhang X, et al. (2019). The association of late-life depression with all-cause and cardiovascular mortality among community-dwelling older adults: systematic review and meta-analysis. \u003cem\u003eBr J Psychiatry. \u003c/em\u003e215(2):449-455. doi:10.1192/bjp.2019.74\u003c/li\u003e\n\u003cli\u003eWu ZJ, Wang ZY, Gao HE, Zhou XF, Li FH. (2021). Impact of high-intensity interval training on cardiorespiratory fitness, body composition, physical fitness, and metabolic parameters in older adults: A meta-analysis of randomized controlled trials. \u003cem\u003eExp Gerontol\u003c/em\u003e. 150:111345. doi:10.1016/j.exger.2021.111345 \u003c/li\u003e\n\u003cli\u003eZou L, SasaKi JE, Wang H, Xiao Z, Fang Q, Zhang M. (2017). A Systematic Review and Meta-Analysis Baduanjin Qigong for Health Benefits: Randomized Controlled Trials. \u003cem\u003eEvid Based Complement Alternat Med\u003c/em\u003e. 2017:4548706. doi:10.1155/2017/454870\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1\u0026nbsp;\u003c/strong\u003eAcceptability of the exercise condition (n = 14)\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"652\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eQuestionnaire item\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eDisagree\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003en (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eNeutral\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003en (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAgree\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003en (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e1. I feel satisfied with the exercise condition that I was allocated to\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e5 (71.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e2. I would have preferred to be in the other exercise condition\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e3. I found the exercise enjoyable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e6 (85.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e5 (71.4%)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e4. I found the exercise too hard\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e6 (85.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e6 (85.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e5. I found the exercise boring\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e6 (85.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e6. I would have preferred group-based exercise\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e5 (71.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e3 (42.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e4 (57.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e7. I looked forward to the exercise sessions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e6 (85.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e8. I would like to continue doing this kind of exercise outside of the study\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e5 (71.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e9. I would feel confident doing this kind of exercise without assistance\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e3 (42.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e4 (57.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e4 (57.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"42.02453987730061%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e10. I would feel confident being able to do this kind of exercise when having a bad day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.417177914110429%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.570552147239264%\" valign=\"top\"\u003e\n \u003cp\u003e5 (71.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.867724867724867%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.132275132275133%\" valign=\"top\"\u003e\n \u003cp\u003e4 (57.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eNote:\u003c/strong\u003e HIIT: high-intensity interval training; MICT-BDJ: moderate-intensity continuous training-Baduanjin.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u0026nbsp;\u003c/strong\u003eBaseline characteristics of the study sample by group allocation.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"596\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n = 20)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eHIIT\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n = 7)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMICT-BDJ\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n = 7)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eRW\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n = 6)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eAge, years, mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e69.9 (3.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e70.1 (3.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e68.3 (4.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e71 (1.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eFemale, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e18 (90%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e5 (71.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e6 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eMarital status, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eSingle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e5 (25%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eMarried\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e11 (55%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e4 (57.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e4 (57.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e5 (83.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eDivorced/widowed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e4 (20%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e1 (16.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eEducation level, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003ePrimary or below\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e5 (25%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e3 (50%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eMiddle or high school\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e12 (60%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e3 (42.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e6 (85.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e3 (50%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eCollege or above\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e3 (15%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eOccupational status\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eEmployed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e1 (5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e1 (14.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eUnemployed/Retired\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e19 (95%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e6 (85.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e6 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eHousehold income, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;HK$20,000/month\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e18 (90%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e7 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e5 (71.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e6 (100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026ge;HK$20,000/month\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e2 (10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e2 (28.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"33.27731092436975%\" valign=\"top\"\u003e\n \u003cp\u003eBMI, kg/m\u003csup\u003e2\u003c/sup\u003e, mean (SD)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"18.991596638655462%\" valign=\"top\"\u003e\n \u003cp\u003e23.1 (2.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.966386554621849%\" valign=\"top\"\u003e\n \u003cp\u003e23.9 (2.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"17.478991596638654%\" valign=\"top\"\u003e\n \u003cp\u003e21 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.285714285714286%\" valign=\"top\"\u003e\n \u003cp\u003e24.7 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eNote. HIIT = high-intensity interval training; MICT-BDJ = moderate-intensity continuous training-Baduanjin; RW= recreation workshop; SD = standard deviation; BMI = body mass index.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u0026nbsp;\u003c/strong\u003eOutcome data for depressive symptoms and physical fitness.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eOutcome measures\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eHIIT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eRW\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.646536412078152%\" colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003eIntervention effect\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT vs RW\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003eHIIT vs\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eMICT-BDJ\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"14.15752741774676%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.07876370887338%\" valign=\"top\"\u003e\n \u003cp\u003ePre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.07876370887338%\" valign=\"top\"\u003e\n \u003cp\u003ePost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.07876370887338%\" valign=\"top\"\u003e\n \u003cp\u003ePre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.07876370887338%\" valign=\"top\"\u003e\n \u003cp\u003ePost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.07876370887338%\" valign=\"top\"\u003e\n \u003cp\u003ePre\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.07876370887338%\" valign=\"top\"\u003e\n \u003cp\u003ePost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.474576271186441%\" valign=\"top\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.474576271186441%\" valign=\"top\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"8.474576271186441%\" valign=\"top\"\u003e\n \u003cp\u003eTime x group\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.577268195413759%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003ed\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.36889332003988%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003ed\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003eDepressive symptoms\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6.4 (1.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e3.3 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6.9 (3.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e5.7 (3.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6.8 (1.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 20.3\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 0.8\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.450\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 3.7\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.046\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003cstrong\u003e1.32\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003cstrong\u003e1.02\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003eTotal PT z-score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e0.2 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e0.3 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e-0.3 (0.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e-0.1 (0.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e0.1 (0.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e-0.3 (0.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 0.2\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.627\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 4.4\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.030\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 4.5\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.026\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.26\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e-0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e23.9 (2.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e23.5 (2.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e21 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e20.7 (2.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e24.7 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e24.7 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 3.4\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.084\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 5.7\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 1.8\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.189\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003cstrong\u003e0.97\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e-0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003e30s chair stand\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e21.9 (6.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e23.1 (6.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e14.9 (9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e17.3 (5.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e10.8 (5.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e12.5 (6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 4.8\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.043\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 4.7\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.023\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 0.2\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.840\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e-0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e-0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003e30s arm curl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e21.7 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e24.4 (5.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e14.3 (5.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e16.7 (4.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e14 (4.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e13 (4.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 2.1\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.167\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 6.8\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 1.5\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.255\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.01\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003e2min step\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e83.1 (17.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e103.6 (9.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e71 (19.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e94.1 (22.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e55.8 (35.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e63 (34.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 6.8\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 5\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.020\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 0.5\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.590\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e0.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e-0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003eChair sit-and-reach\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6.9 (11.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e10 (9.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e13.6 (8.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e13.9 (13.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e11.6 (7.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e-0.1 (9.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 1.4\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.252\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 1.4\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.285\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 3.7\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.048\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e0.38\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003eBack scratch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e5.1 (7.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e5.4 (5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6 (2.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6.9 (4.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e11.4 (5.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e-0.8\u0026nbsp;(8.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 4.1\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 0.2\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.840\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 5.3\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e1.29\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e-0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"10.923623445825932%\" valign=\"top\"\u003e\n \u003cp\u003e8ft up-and-go\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.61101243339254%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e5.8 (1.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e5.3 (0.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e5 (1.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e5.4 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6.6 (1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.30550621669627%\" valign=\"top\"\u003e\n \u003cp\u003e6.7 (1.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e1,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 0.1\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.936\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 4.5\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.027\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"7.548845470692718%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cem\u003eF\u003csub\u003e2,17\u0026nbsp;\u003c/sub\u003e\u003c/em\u003e= 2\u003c/p\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e = 0.162\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"6.74955595026643%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003cstrong\u003e0.84\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.236234458259325%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003cstrong\u003e1.17\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eNote. Pre and post are mean (SD); \u003cem\u003ed\u003c/em\u003e = standardized change score expressed as Cohen\u0026rsquo;s \u003cem\u003ed\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003eAbbreviations: HIIT = high-intensity interval training; MICT-BDJ = moderate-intensity continuous training-Baduanjin; RW = recreation workshop; PT = physical fitness.\u003c/p\u003e\n\u003cp\u003eBold values signify moderate or large effect sizes.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[{"identity":"309132fa-9303-4f36-9238-193e31dfe401","identifier":"10.13039/501100002920","name":"Research Grants Council, University Grants Committee","awardNumber":"12616922","order_by":0}],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Hong Kong Baptist University","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"High-intensity interval training, Baduanjin Qigong, Exercise intervention, depressive symptoms, physical fitness, feasibility","lastPublishedDoi":"10.21203/rs.3.rs-4160308/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4160308/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground and aims:\u003c/h2\u003e \u003cp\u003eOlder adults with mild-to-moderate depressive symptoms (MMDS) are at high risk to develop severe depression along with mortality and disability. The aim of this study was to investigate the feasibility and effects of high intensity interval training (HIIT) in older adults with MMDS.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThree elderly centers involving 24 older adults with MMDS were randomized into: 1) HIIT (n\u0026thinsp;=\u0026thinsp;8); 2) moderate-intensity continuous training (Baduanjin Qigong) (MICT-BDJ) (n\u0026thinsp;=\u0026thinsp;8); or 3) recreation workshop (RW) control (n\u0026thinsp;=\u0026thinsp;8) for a 16-week (32 session) intervention. Feasibility was assessed using retention rate, session attendance rate, exercise intensity adherence, acceptability, and safety. Self-reported depressive symptoms and objectively measured physical fitness (PF) were assessed at baseline and post-intervention.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003e20 participants completed data collection twice. The retention rate was 87.5% (7/8), 87.5% (7/8), 75% (6/8) for HIIT, MICT-BDJ, and RW, respectively. 87.5% (7/8) of HIIT participants completed at least 75% of exercise sessions. 81.4% of HIIT participants achieved the pre-designed intensity (\u0026ge;\u0026thinsp;80% maximum heart rate) during the high-intensity intervals. All HIIT (7/7) participants were satisfied with their group allocation. More HIIT (6/7) than MICT-BDJ (5/7) participants found the exercise enjoyable. Two mild adverse events were reported in the HIIT group. HIIT improved depressive symptoms more than MICT-BDJ (\u003cem\u003ed\u003c/em\u003e = \u003cb\u003e-\u003c/b\u003e1.02) and RW (\u003cem\u003ed\u003c/em\u003e = \u003cb\u003e-\u003c/b\u003e1.32). Both HIIT (\u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.26) and MICT-BDJ (\u003cem\u003ed\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.39) improved PF more than RW.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eHIIT was feasible and effective in improving the depressive symptoms and PF for older adults with MMD.\u003c/p\u003e\u003ch2\u003eTrial registration:\u003c/h2\u003e \u003cp\u003eThis study was registered on the ClinicalTrials Registry (NCT06014294).\u003c/p\u003e","manuscriptTitle":"Feasibility and Effects of High-Intensity Interval Training in Older Adults with Mild to Moderate Depressive Symptoms: A Pilot Cluster-Randomized Controlled Trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-03-26 20:52:21","doi":"10.21203/rs.3.rs-4160308/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7bfa4cb6-7330-42b9-a7a2-eaa2ae798e08","owner":[],"postedDate":"March 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":29829856,"name":"Preventive Medicine"}],"tags":[],"updatedAt":"2024-03-26T20:52:22+00:00","versionOfRecord":[],"versionCreatedAt":"2024-03-26 20:52:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4160308","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4160308","identity":"rs-4160308","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}