Higher Inhalation/Exhalation Ratio during Spontaneous Breathing Associates to Poor Mental Health in University Students

Higher Inhalation/Exhalation Ratio during Spontaneous Breathing Associates to Poor Mental Health in University Students | 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 Higher Inhalation/Exhalation Ratio during Spontaneous Breathing Associates to Poor Mental Health in University Students Wen-Ming Liang, Kai Jiang, Adomas Hendrikson, Inga Truskauskaitė, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5844007/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Background Breathing exercises, particularly those involving altered inhalation/exhalation duration ratios (I/E ratios) and increased abdominal movement, have demonstrated the potential for alleviating symptoms of mental health issues. However, it remains unclear which approach is more effective. This study aims to examine how resting respiratory patterns (e.g., I/E ratios and abdominal movement) relate to mental health, potentially guiding psychologists in recommending tailored breathing exercises. Methods A total of 240 university students (120 male and 120 female) were recruited by systematic sampling. The I/E ratio and the contribution of abdominal movement to the sum of abdominal and thoracic movements AM/(AM + TM) were recorded by respiration belts, while depression, anxiety, and stress levels were assessed with the DASS-21. Data were analyzed for each gender; each gender being categorized into either a low or high level symptom category. Results Women with high stress symptoms exhibited significantly lower I/E ratios (a lower I/E ratio indicates breathing with relatively shorter inhalation and longer exhalation) compared to those with lower stress symptoms (n = 117, F = 4.198, p = 0.043, ηp² = 0.035). A negative correlation was observed between I/E ratios and depression in women (n = 117, r = -0.211, p = 0.023). For students with high anxiety symptoms, I/E ratios were negatively correlated with anxiety scores in both men (n = 61, r = -0.292, p = 0.022) and women (n = 70, r = -0.392, p < 0.001). There were no substantial correlations between abdominal movement and mental health. Conclusions In general, university students who exhibit relatively shorter inhalations and longer exhalations tend to have poorer mental health, especially among women; This respiratory pattern may represent an autonomic compensatory strategy for coping with psychological distress. More attention could be devoted to breathing exercises involving altered I/E ratios as part of mental health management programs. inhalation/exhalation ratio abdominal movement stress anxiety depression Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1 Introduction Mental health problems are highly prevalent among university students [ 1 – 3 ], with depression, anxiety, and stress among the most common [ 4 ]. In 2018, it was reported that around 20% of university students in the United States experienced suicidal thoughts [ 5 ]. In a 2020 insight network survey across 10 universities in the UK, findings showed that "1 in 5 students has a current mental health diagnosis," with "almost half experiencing a serious psychological issue requiring professional help"—a rise from 1 in 3 in the 2018 survey [ 6 ]. There was also an alarmingly high degree of students who have suffered from depressive disorders and anxiety problems in China [ 7 ]. Li Gao and colleagues (2020) conducted a meta-analysis by searching four electronic databases and selecting 113 studies, revealing an overall prevalence of depression among Chinese university students of 28.4%, with a 95% confidence interval of 25.7–31.2% [ 8 ]. Gao and colleagues (2021) conducted a cross-sectional survey of 1,017 first-year Chinese university students, finding prevalence rates of anxiety and depression (ranging from mild to severe) at 40.3% and 45.3%, respectively [ 9 ]. These mental health problems can lead to distress, poor academic performance, and lower job prospects after graduation [ 10 , 11 ]. Therefore, it is vital and urgent to improve the mental health of university students. Practices such as intentional alteration of breathing patterns can positively influence certain mental states prior to pharmaceutical interventions. Two notable examples include abdominal breathing and breathing exercises with prolonged exhalation, both of which have demonstrated efficacy in improving mental health. Abdominal breathing is characterized by the movement of the diaphragm, which intentionally expands the abdominal wall [ 12 ]. The research found that abdominal breathing can reduce stress by lowering the pulse rate and blood pressure, improving vagal activity, and reducing the sympathetic reaction, offering a non-pharmacologic intervention to mitigate psychological stress [ 13 ]. Also, abdominal breathing has been associated with alleviating anxiety and depressive symptoms [ 14 ]. In addition, abdominal breathing has been shown to improve sustained attention, affect, and cortisol levels, indicating reduced stress and enhanced mental function in healthy individuals [ 15 ]. The phrenic nerve that innervates the functions of the diaphragm has a connection with the vagus nerve, which can affect the whole-body system [ 16 ]. Diaphragmatic motion in breathing, directly or indirectly, affects the sympathetic and parasympathetic nervous systems and also influences motor nerve activities and brain mass [ 17 ]. These might be the basis of the influence of abdominal breathing on mental health. As for the breathing method with altered inhalation and exhalation duration, participants in a study reported increased relaxation, stress reduction, mindfulness, and positive energy when breathing with a low I/E ratio compared to a high I/E ratio [ 18 – 21 ]. The processes of inhalation and exhalation have distinct effects on the autonomic nervous system. During exhalation, the increased pressure in the chest cavity raises blood pressure, [ 22 ], which activates the aortic arch baroreceptors and increases the stimulation of the nucleus tractus solitarius. This, in turn, leads to increased excitation of parasympathetic efferent signals. Conversely, the effect of inhalation on sympathetic activity has a corresponding, reverse effect [ 23 – 25 ]. While both breathing exercises exhibit the potential for alleviating mental health symptoms, the most suitable option remains unclear. Exploring the relationship between resting respiratory patterns (including I/E ratio and the contribution of abdominal movement to total respiratory movement) and mental health could aid psychologists in prescribing suitable breathing exercises. A lot of research has been done on the relationship between mental health and resting respiratory patterns. The Trimodal Anxiety Questionnaire (TAQ) assesses anxiety in three dimensions: cognitive, physiological, and behavioral. The Self-Evaluation of Breathing Questionnaire (SEBQ) screens for faulty breath patterns. Jamie E. and colleagues found a positive correlation between TAQ and SEBQ (n = 79, r = 0.49, p < 0.05) [ 26 ]. The limitation of this finding is that it did not show which breathing pattern is specifically associated with anxiety. Akae Kato and colleagues found that inhalation and exhalation durations were significantly shorter in both higher trait and higher state anxiety groups compared to the lower trait and lower state anxiety groups [ 27 ]. However, this study did not investigate the I/E ratio. Also, this research enrolled 16 male participants, and the authors did not specify the number of participants in higher and lower anxiety categories. Therefore, larger sample sizes can help verify these findings and provide more information for further studies. Hence, the present study seeks to investigate the connection between resting respiration patterns (I/E ratio, abdominal movement contribution) and mental health among university students. Masaoka and colleagues found that, in the high-anxiety group, there were negative correlations between expiratory time and anxiety scores in both physical load and the noxious audio stimulation tests [ 28 ]. In another experiment, Masaoka and colleague also found anticipatory anxiety (triggered by an electrical stimulus) decreases the expiratory duration, but not inspiration duration, in both low and high trait anxiety groups [ 29 ]. Therefore, we expect that people with higher levels of anxiety would display shorter exhalation durations during resting breathing and that people with lower levels of anxiety would display greater abdominal movement. 2 Methods 2.1 Study design and participants 2.1.1 Study design The current research is a cross-sectional study focusing on the relationship between university students’ resting breathing patterns and their mental health. A total of 240 university students (120 of each sex, aged 18–22) were recruited through random cluster sampling from the Physical Exercises course at Zhejiang University in September and October 2023. The procedure is outlined in Fig. 1 . 2.1.2 Sample size estimation The sample size was determined using G*Power version 3.1.9.7. Given that the primary statistical method was correlation analysis and the decision to analyze men and women separately, a medium effect size (Cohen’s ρ = 0.30), a two-tailed significance level of 0.05, and a power of 0.90 were applied [ 30 ]. Based on these assumptions, 109 participants were needed. Accounting for a 10% drop-out rate, the required sample size was set at 120 participants for each sex. 2.1.3 Sampling method Physical exercises courses are mandatory for all students at Zhejiang University, but students can choose their preferred sporting activity within these courses. The available sports courses can be broadly categorized into six groups according to the character of the sports (e.g., football, basketball, and rugby were in one group of exercises). In total, there were 474 physical exercise classes, with approximately 30 students in each class. In order to obtain a representative sample, the current study randomly selected 18 classes, with three classes selected from each group of exercises. Students were recruited sequentially from each group of exercises until 20 students of each gender had been enlisted, reaching a total sample size of 240 students. 2.1.4 Inclusion and exclusion The inclusion criteria for participants were as follows: being 18–22 years old; the absence of musculoskeletal or cardiorespiratory diseases; female participants taking the test on days 3–10 after the end of menstruation; having providing written informed consent. The exclusion criteria included: recent or ongoing acute diseases without physical recovery; consumption of coffee or tea within 2 hours prior to the tests; and inability to perform 2 minutes of consecutively stable respiratory cycles. To minimize the effect of different time periods on students' physiological and psychological states, participants were required to perform the test from 8:00 to 12:00 on Saturdays and Sundays. 2.1.5 Ethics and consent This study was conducted in accordance with the Declaration of Helsinki and approved by the Research Ethics Committee of Zhejiang University (Approval Number: 2023-039). All participants provided written informed consent and consented to use their clinical and demographic data for publication. 2.2 Measures 2.2.1 Respiratory testing and data processing. Respiratory belts (Vernier, Beaverton, OR, USA) were used to assess respiratory patterns. These belts were made of fabric with a resistive stretch sensor embedded in them and could be used to measure the respiration rate and breathing maneuvers. Two belts were employed for the current investigation: one was secured at the xiphoid process level and the other at the navel level to monitor the thoracic and abdominal motions, as shown in Fig. 2 . The participants were instructed to sit quietly for 5 min before testing to ensure that they were mentally and physically calm. The subjects were asked to complete the test standing upright to eliminate the impact of abdominal circumference on the measurements. In accordance with the user guide, a researcher adjusted the straps until the lights on the belt turned green. During the test, the participants watched a neutral video on an 11-inch Xiaomi Pad (resolution:2560 × 1600; Xiaomi, Beijing, China) that was placed 50–80 cm in front of them to divert their attention from breathing. The respiration test lasted for 3 minutes. We observed that the respiration waves became more regular 30 seconds after the start of the test. Consequently, we took data from the 40th second to the 160th second (2 minutes in total) to calculate the breathing pattern. A MATLAB App Designer program (Matlab 2022a, Mathworks, Natick, MA, USA) was written to process the raw data and compute results. To calculate the respiration rate (RR), inhalation duration (ID), and exhalation duration (ED), the Kernel distribution (smoothing) was computed using the formula \(\:{\widehat{f}}_{h}\left(x\right)=\frac{1}{nh}\sum\:_{i=1}^{n}K\left(\frac{x-{x}_{i}}{h}\right)\) , for reducing the effect of noise. An h-value of 0.25 was empirically selected as the most appropriate. Then, code was written to find maximum values (peaks) where inspiration ended and minimum values (troughs) where expiration began. The inhalation duration (ID) was determined by subtracting the time of a peak from its preceding trough, and subsequently obtaining an average from the cumulative IDs (Fig. 3 ). Conversely, the exhalation duration (ED) was computed by subtracting the time of a trough from its preceding peak and averaging the totality of the accrued EDs. The I/E ratio was then derived by dividing ID by ED. The respiratory rate (per minute) was calculated by subtracting the time at which the first peak occurred from the time at which the last peak occurred, dividing it by the number of breaths taken in between to find the time for one breath, and finally dividing 60 by the time taken for one breath. To maintain as much data integrity as possible we used the raw data to calculate the thoracic and abdominal movements. This was done because the raw data does not affect the force values, whereas using smoothing processes would. Peaks and troughs were identified in their respective waveforms (Fig. 4 ). The force of the thoracic movement was determined by subtracting the average of all trough values from the average of all peak values for thoracic movement. Abdominal movements were calculated using an identical approach. 2.2.2 Mental health testing The 21-item Depression, Anxiety, and Stress Scales (DASS-21) were used to measure mental health indicators; 7 items for each scale (depression, anxiety, and stress) [ 32 – 34 ]. The Chinese version of DASS-21 has been tested and confirmed to be a valid, reliable and effective tool for assessing depression, anxiety, and stress in adult residents of mainland China (Cronbach's α was 0.912; the mean inter-item correlation coefficient was 0.338; the test-retest Pearson correlation coefficient was 0.751.) [ 32 ]. The answers were reported on a four-point scale, from 0 (“did not apply to me at all”) to 3 (“applied to me very much, or most of the time”). As the DASS-21 is a short version of the original 42-item DASS form, to characterize the severity levels relative to the population, the scores on DASS-21 were multiplied by two and compared with the cutoff values of conventional severity labels. We divided DASS-21 scores into two symptom groups for anxiety (high = score ≥ 8, low = score < 8), stress (high = score ≥ 15, low = score < 15), and depression (high = score ≥ 10, low = score < 10), according to previous studies [ 35 , 36 ]. In this study, we calculated Cronbach's alpha coefficients (α) for stress (overall α = 0.65; male α = 0.64; female α = 0.66), anxiety (overall α = 0.76; male α = 0.79; female α = 0.72), and depression (overall α = 0.69; male α = 0.69; female α = 0.69). The results indicated that the internal consistency of each psychological parameter was acceptable. 2.3 Statistical Analysis At first, we tested the distribution of the data. Skewness and kurtosis scores indicated univariate normality: values for skewness were within the range of +/- 2 and kurtosis within the range of +/-7. [ 37 – 39 ]. Homogeneity was checked with the Homogeneity of Variance Test. Then, the General Linear Model Univariate Test was used to compare the respiratory and psychological parameters between men and women, and to compare the respiratory patterns between low and high symptom groups of mental health. The level of significance was set at p < 0.050. The effect sizes of the partial eta squared were interpreted as small (η²p = 0.01), medium (η²p = 0.06), and large (η²p = 0.14) [ 40 ]. Before testing for correlation, the linearity was tested using linear regression. This was achieved by comparing the F-value generated from respiratory and psychological parameters with the F-value obtained from the squared respiratory parameters and psychological parameters. If the change in F-value was significant ( p < 0.05), the relationship between the respiratory parameter and psychological parameter was quadratic; otherwise, the relationship was regarded as linear, as previously described [ 41 – 43 ]. Then, Pearson correlation was used for correlation analyses, and significance was set as p < 0.025 (Bonferroni correction). 3 Results 3.1 Data description and comparison between men and women One male and two female participants had unnaturally forceful breathing, and one female student’s psychological questionnaire was missing. As a result, these participants were excluded, leaving a total of 119 male and 117 female participants. As shown in Table 1, there were significant differences in body height, weight, every respiration pattern parameter and the score of anxiety between male and female participants. Thus, we analyzed the data separately for each sex. Table 1. Data description and comparison between men and women. Men Women All parameters n Mean±SD n Mean±SD F p ɳ²p Age (year) 119 19.8±0.83 117 19.9±0.80 0.48 0.488 0.002 Height(cm) 119 174±6.17 117 162±5.29 244 <0.000 0.510 Weight (kg) 119 64.8±8.90 117 54.7±6.83 94.9 <0.000 0.289 BMI (kg/m 2 ) 119 21.4±2.47 117 20.8±2.32 3.78 0.053 .016 I/E ratio 119 0.85±0.11 117 0.78±0.11 21.7 <0.000 0.085 AM/(AM+TM) 119 0.41±0.14 117 0.35±0.11 15.4 <0.000 0.062 DASS-Stress 119 11.1±5.88 117 11.6±5.71 0.44 0.510 0.002 DASS-Anxiety 119 7.83±4.65 117 9.18±5.09 4.51 0.035 0.019 DASS-Depression 119 6.34±6.25 117 6.80±5.29 0.38 0.536 0.002 Notes: AM/(AM+TM), proportion of abdominal motion to the sum of abdominal and thoracic motions; BMI, body mass index; I/E ratio, ratio of inhalation duration to exhalation duration; ɳp², the partial eta squared. 3.2 The comparison of the respiratory patterns between low and high symptom groups in men and woman We categorized the DASS-21 scores into two symptom groups for anxiety (high: score ≥ 8, low: score < 8), stress (high: score ≥ 15, low: score < 15), and depression (high: score ≥ 10, low: score < 10) based on previous studies [35,36]. As shown in Table 2, women with high stress scores (n = 86) exhibited a lower I/E ratio than those with low stress scores (n = 31). In addition, we found no significant differences in solely inhalation duration and solely exhalation duration between low and high anxiety scores in women ( p < 0.05), suggesting that women with higher stress scores tend to have relatively shorter inspiration and longer exhalation. Except for this finding, there were no significant differences in the other comparisons. Table 2. The comparison of the respiratory patterns between participants displaying low and high levels of mental health symptoms. Respiratory patterns Low symptoms scores High symptoms scores F p η 2 p Men Stress (n=87) Stress (n=32) I/E ratio 0.85±0.11 0.84±0.12 0.27 0.603 0.002 AM/(AM+TM) 0.41±0.14 0.42±0.15 0.20 0.653 0.002 Anxiety(n=57) Anxious (n=62) I/E ratio 0.85±0.11 0.85±0.12 0.00 0.982 0.000 AM/(AM+TM) 0.39±0.13 0.43±0.15 2.37 0.127 0.020 Depression (n=91) Depression (n=28) I/E ratio 0.85±0.11 0.85±0.12 0.04 0.839 0.000 AM/(AM+TM) 0.41±0.14 0.44±0.14 1.17 0.282 0.010 Women Stress (n=86) Stress (n=31) I/E ratio 0.79±0.11 0.74±0.12 4.20 0.043 0.035 AM/(AM+TM) 0.35±0.11 0.34±0.11 0.35 0.555 0.003 Anxiety (n=47) Anxious (n=70) I/E ratio 0.77±0.11 0.79±0.12 0.88 0.351 0.008 AM/(AM+TM) 0.35±0.11 0.35±0.11 0.01 0.925 0.000 Depression (n=88) Depression (n=29) I/E ratio 0.79±0.11 0.75±0.13 2.53 0.115 0.022 AM/(AM+TM) 0.34±0.11 0.36±0.12 0.59 0.445 0.005 Notes: AM/(AM+TM), proportion of abdominal motion to the sum of abdominal and thoracic motions; I/E ratio, ratio of inhalation duration to exhalation duration; ɳp², the partial eta squared. 3.3 The correlation between respiratory patterns and mental health in men and women According to the method for testing linearity, we found that the relations between every respiratory parameter and every psychological parameter were linear, thus Pearson correlational analysis was further applied. There was only one significant correlation between the I/E ratio and depression in women, as shown in Table 3. This correlation indicates that, for female university students (all enrolled women, n=117), those with higher depression scores tend to have a lower I/E ratio (i.e., relatively shorter inhalation and longer exhalation). Table 3. The correlation coefficients between respiratory patterns and mental health in all participants. Men (n) AM/(AM+TM) I/E ratio Women (n) AM/(AM+TM) I/E ratio Stress 119 r = 0.154 p = 0.094 r = - 0.023 p = 0.800 117 r = 0.021 p = 0.824 r = -0.144 p = 0.120 Anxiety 119 r = 0.173 p = 0.060 r = -0.112 p = 0.226 117 r = -0.024 p = 0.795 r = -0.124 p = 0.185 Depression 119 r = 0.166 p = 0.071 r = -0.031 p = 0.737 117 r = -0.029 p = 0.755 r = -0.211 p = 0.023 3.4 The correlation between respiratory patterns and mental health in low and high symptom groups Then we stratified each sex into low and high symptom groups and tested the correlation between respiratory pattern and mental health. With respect to anxiety, for both men and woman in high anxiety symptom groups, the scores of anxiety and I/E ratios were significantly and negatively correlated (n = 62, r = -0.289, p = 0.023); n = 70, r = -0.392, p < 0.001 for women), as shown in Figure 5 and 6. Due to the significant correlation between the body height and I/E ratios in women (n = 70, r = -0.298, p = 0.012), we calculated the residuals of body height and I/E ratios and then tested the correlation of those residuals with the scores of anxiety. The result of the correlation was r = -0.390, p < 0.001, which indicated that the body height did not influence the correlation between I/E ratios and the anxiety scores. Both stress and depression were not significantly correlated with respiratory patterns for both men and women, in neither the low symptom or high symptom group ( r 0.05). 4 Discussion The aim of the current study was to test the relationship between mental health (stress, anxiety, and depression) and resting respiratory patterns (I/E ratio and (AM/(AM + TM)), which could assist professionals in recommending appropriate breathing exercises for managing mental issues in university students. A significant negative correlation between anxiety scores and I/E ratios among students with high anxiety symptoms was observed and evident in both men and women. Besides, the I/E ratio was significantly higher in women in the low stress symptom category than in those in the high stress symptom category, but no substantial correlations between I/E and stress were observed. In addition, female students with lower depression scores tend to exhibit a smaller I/E ratio, characterized by relatively shorter inhalations and longer exhalations. The negative correlation between anxiety and I/E ratio in students displaying elevated anxiety symptoms is contrary to what we expected. Studies found that during prolonged expiratory breathing, parasympathetic nervous function was significantly activated [ 44 ], and the elevated parasympathetic nervous function promoted relaxation [ 45 ]. Thus, people with lower I/E ratios were expected to be more relaxed. There could be two possible explanations for our observation. At first, the shortened exhalation duration triggered by the noxious audio stimulation (anticipatory anxiety) cannot indicate a shorter exhalation during resting breathing for anxious people, referring to the studies conducted by Masaoka and Homma [ 28 , 29 ]. Secondly, the relationship between anxiety levels and the I/E ratio during spontaneous breathing may differ from the relationship observed during controlled breathing, referring to previous researches [ 18 – 21 ]. We suggest that the observed resting respiratory pattern (shorter inhalation combining longer exhalation) might be an autonomically compensatory strategy to cope with anxiety, similarly to “sighing”. Sighing seems to act as a psychophysiological reset mechanism, restoring homeostatic balance when it has been compromised [ 46 – 49 ]. In humans, sighs were reported to be associated with anxiety, fear and resentment [ 50 ]. Compared to healthy controls, individuals reporting relatively high anxiety sensitivity, suffering from chronic anxiety exhibit more frequent sighing than healthy individuals under rest or stress conditions [ 51 – 53 ]. Sighing is characterized by deep breaths followed by extended, relatively longer exhales [ 54 ], from which it can be deduced that relatively longer exhalation duration in sighing can decrease the level of anxiety. Sighing restores lung compliance and gas exchange efficiency and reduces hypoxia and hypercapnia [ 55 ], while the resting respiration pattern with relatively shorter inhalation duration and longer exhalation duration might also has these effects. Respiratory changes in response to anxiety are affected by higher centres related to the emotion [ 56 ]. Stimulation of the amygdala produces a rapid increase in respiratory rate followed by a feeling of fear and anxiety [ 57 ]. The piriform cortex may produce rhythms, and the piriform–amygdala complex may alter respiratory rhythm in response to qualitative changes in emotions [ 56 ]. These brain structures may be associated with changes in breathing patterns when coping with anxiety. A significantly higher I/E ratio in women with low stress symptoms (n = 86) compared to those with high stress symptoms (n = 31) supports the negative correlation between the I/E ratio and anxiety scores as presented above. The current study is only a preliminary exploration of the topic. There were only 31 female participants in the high stress symptom category. Future studies may enroll more participants who have high stress symptom to verify our results. Additionally, as our sample size of participants displaying elevated depression symptoms was quite small (n = 29), future studies can also enroll more participants in this category. In addition, our study found that the correlation between the I/E ratio and mental health is stronger in women than in men. The results in Table 1 showed that men generally exhibited better mental health than women, particularly concerning anxiety, which was consistent with findings from other studies [ 7 , 58 ]. Additionally, we observed that men's I/E ratio was higher than that of women, in line with our previous research [ 59 ]. Thus, we suggest that the stronger correlation may be attributed to the more severe mental symptoms experienced by women. 5 Limitations This is preliminary research. We randomly enrolled participants and found that the population with high stress scores and high depression scores was not substantial. Future studies may enroll more participants who have high stress scores and/or high depression scores. 6 Conclusions In general, university students who exhibit relatively longer inhalation and shorter exhalation tend to have better mental health, especially among women. This respiratory pattern may represent an autonomic compensatory strategy to cope with psychological distress. More attention could be devoted to breathing exercises involving altered I/E ratios for mental health management. Declarations Acknowledgments The authors sincerely thank all the participants. Special thanks to Yu-Xuan Ouyang, Yi-Wen Xi, Hua-Yang Fan, Yan Zhang, Jia-Xiang He, Xi-Ya Sun, and Xuan-Xue He for data collection, and to Xie Zeng for making Figure 2. Author Contributions OR, WL, YD, KJ, IT, JX, FR, and IG contributed to the conceptualization and methodology. YD, KJ, WL, and AH contributed to data collection and processing. WL and IT contributed to the formal analysis. WL, KJ, and YD wrote the original draft; YD, OR, IG, IT, AH, JX, and FR reviewed and edited the manuscript. All authors have read and agreed to the published version of the manuscript. Funding: Wenming Liang and Jing Xiao was funded by the Capital’s Funds for Health Improvement and Research (2022-2-4175) in China. Wenming Liang was also funded by Jimei University in China and Vilnius University in Lithuania; Yinling Du was funded by Hangzhou Normal University, China; Kai Jiang was funded by Zhejiang University, China. Data Availability Statement The data that support the findings of this study are available on request from the corresponding author Yin-Ling Du. Ethics approval and consent to participate This study was conducted in accordance with the Declaration of Helsinki and approved by the Research Ethics Committee of Zhejiang University (Approval Number: 2023-039). 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Cell Rep Med 2023 , 4 , 100895, doi:10.1016/j.xcrm.2022.100895. Cherniack, N.S.; von Euler, C.; Głogowska, M.; Homma, I. Characteristics and Rate of Occurrence of Spontaneous and Provoked Augmented Breaths. Acta Physiol Scand 1981 , 111 , 349–360, doi:10.1111/j.1748-1716.1981.tb06747.x. Homma, I.; Masaoka, Y. Breathing Rhythms and Emotions. Exp Physiol 2008 , 93 , 1011–1021, doi:10.1113/expphysiol.2008.042424. Champagnat, J. Post-Genomic Perspectives in Modeling and Control of Breathing. In Proceedings of the Post-Genomic Perspectives in Modeling and Control of Breathing; Champagnat, J., Denavit-Saubié, M., Fortin, G., Foutz, A.S., Thoby-Brisson, M., Eds.; Springer US: Boston, MA, 2005; pp. 323–326. Zhan, H.; Zheng, C.; Zhang, X.; Yang, M.; Zhang, L.; Jia, X. Chinese College Students’ Stress and Anxiety Levels Under COVID-19. Front Psychiatry 2021 , 12 , 615390, doi:10.3389/fpsyt.2021.615390. Liang, W.-M.; Ji, Y.-X.; Xiao, J.; Truskauskaitė, I.; Hendrixson, A.; Bai, Z.-M.; Ruksenas, O. Respiratory Patterns and Physical Fitness in Healthy Adults: A Cross-Sectional Study. BMC Public Health 2024 , 24 , 228, doi:10.1186/s12889-024-17687-8. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 21 Nov, 2025 Reviews received at journal 29 Oct, 2025 Reviewers agreed at journal 19 May, 2025 Reviewers agreed at journal 15 May, 2025 Reviews received at journal 09 May, 2025 Reviewers agreed at journal 01 May, 2025 Reviewers invited by journal 26 Apr, 2025 Editor invited by journal 01 Apr, 2025 Editor assigned by journal 23 Jan, 2025 Submission checks completed at journal 17 Jan, 2025 First submitted to journal 16 Jan, 2025 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-5844007","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":403490871,"identity":"fdc1ec20-bd97-47ae-92e1-5c0b1ac6acdd","order_by":0,"name":"Wen-Ming Liang","email":"","orcid":"","institution":"Jimei University","correspondingAuthor":false,"prefix":"","firstName":"Wen-Ming","middleName":"","lastName":"Liang","suffix":""},{"id":403490872,"identity":"b94fcabc-d998-48e2-9709-c0cdcb82a6ba","order_by":1,"name":"Kai Jiang","email":"","orcid":"","institution":"Zhejiang University","correspondingAuthor":false,"prefix":"","firstName":"Kai","middleName":"","lastName":"Jiang","suffix":""},{"id":403490873,"identity":"6f872673-f4d1-436a-b465-b02f7bd853bf","order_by":2,"name":"Adomas Hendrikson","email":"","orcid":"","institution":"Vilnius University","correspondingAuthor":false,"prefix":"","firstName":"Adomas","middleName":"","lastName":"Hendrikson","suffix":""},{"id":403490874,"identity":"777cfdac-5806-4ae2-a69f-550c716a077c","order_by":3,"name":"Inga Truskauskaitė","email":"","orcid":"","institution":"Vilnius University","correspondingAuthor":false,"prefix":"","firstName":"Inga","middleName":"","lastName":"Truskauskaitė","suffix":""},{"id":403490875,"identity":"ecfe4126-5b7d-455e-808d-aea5d4b214a3","order_by":4,"name":"Inga Griškova-Bulanova","email":"","orcid":"","institution":"Vilnius University","correspondingAuthor":false,"prefix":"","firstName":"Inga","middleName":"","lastName":"Griškova-Bulanova","suffix":""},{"id":403490876,"identity":"ab683027-2c0f-4be5-8c57-dc2150b47cb6","order_by":5,"name":"Jing Xiao","email":"","orcid":"","institution":"Chinese Academy of Chinese Medical Sciences","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Xiao","suffix":""},{"id":403490877,"identity":"109c8f06-2553-4745-819f-06664db6d160","order_by":6,"name":"Fei-Fei Ren","email":"","orcid":"","institution":"Beijing Language and Culture University","correspondingAuthor":false,"prefix":"","firstName":"Fei-Fei","middleName":"","lastName":"Ren","suffix":""},{"id":403490878,"identity":"6a772fe5-1cc9-4a2f-be65-7cfc0c72e68b","order_by":7,"name":"Yin-Ling Du","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5klEQVRIie3RMWrDMBSAYRmBsrzi9ZnUd1AROItJriITsK/gMRBwtswK5BA+gkCQLD6AIRkCAU8ZcoP0lW6lyO7WQf/0EPoGPTEWCv3DYs6t1TKHGL8Pos0YSXZNcXvW5XtiphLZderDdC6X/VTCep3N3xoO6rIb7sDytLV8uPlEZHRJREB2tZUCVqrWioX0EY76RAQg62kA5orWgkAfEVg0RBCUoQHYa5wAOE7PlyBxLYjYcYKzJqIla8C+FMlRrtXBicxLVi5+0le+VrGpBnzUy3R/3g5e8qOvVfE/3A+FQqHQ730CzTxGNd3CxaIAAAAASUVORK5CYII=","orcid":"","institution":"Hangzhou Normal University","correspondingAuthor":true,"prefix":"","firstName":"Yin-Ling","middleName":"","lastName":"Du","suffix":""},{"id":403490879,"identity":"c5e70da1-f8d8-40d7-b478-07ff20bd61ed","order_by":8,"name":"Osvaldas Rukšėnas","email":"","orcid":"","institution":"Vilnius University","correspondingAuthor":false,"prefix":"","firstName":"Osvaldas","middleName":"","lastName":"Rukšėnas","suffix":""}],"badges":[],"createdAt":"2025-01-16 18:08:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5844007/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5844007/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":74236447,"identity":"fecdd74d-d1d5-40f5-a778-7f4d2ec28484","added_by":"auto","created_at":"2025-01-20 08:56:45","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1627862,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart showing the study design\u003c/p\u003e","description":"","filename":"Figure1.Flowchartshowingthestudydesign.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5844007/v1/bc004550b435b8e9162a7e37.jpeg"},{"id":74236453,"identity":"7b9d554d-d112-4c1c-9ecb-96bf627a643d","added_by":"auto","created_at":"2025-01-20 08:56:46","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":4640048,"visible":true,"origin":"","legend":"\u003cp\u003eTest of spontaneous respiration. This figure was adapted from our previous publication [31].\u003c/p\u003e","description":"","filename":"Figure2.Testofspontaneousrespiration.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5844007/v1/b0b53025f29ab24536f34228.jpeg"},{"id":74237073,"identity":"3516f932-b0bd-469d-bfbc-f6a19a997883","added_by":"auto","created_at":"2025-01-20 09:04:46","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":714791,"visible":true,"origin":"","legend":"\u003cp\u003eWave lines of respiration: smoothed thoracic motion for calculating inhalation duration, and exhalation duration\u003c/p\u003e","description":"","filename":"Figure3.Wavelinesofrespiration.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5844007/v1/ceff05b87016f714e2de2c59.jpeg"},{"id":74237078,"identity":"db956aae-ce5a-41cd-8f61-cc463f53e2fd","added_by":"auto","created_at":"2025-01-20 09:04:46","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1009904,"visible":true,"origin":"","legend":"\u003cp\u003eWave lines of respiration: raw data for calculating thoracic motion and abdominal motion (P = peak, T = trough)\u003c/p\u003e","description":"","filename":"Figure4.Wavelinesofrespiration2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5844007/v1/0d7af0129c54a181b45e8122.jpeg"},{"id":74236461,"identity":"6db94eeb-ed73-478b-b7bf-ee789b9707db","added_by":"auto","created_at":"2025-01-20 08:56:46","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":481065,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between anxiety scores and I/E ratios in men\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNote:\u003c/strong\u003e As the DASS-21 is a short version of the original 42-item DASS form, to characterize the severity levels relative to the population, the scores on DASS-21 were multiplied by two.\u003c/p\u003e","description":"","filename":"Figure5.AnxietyscoresandIEratiosinmen.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5844007/v1/df42d4503ae5f2030b4ab21c.jpeg"},{"id":74236465,"identity":"98c2c068-0baf-49f7-91cb-3ddd37360b0f","added_by":"auto","created_at":"2025-01-20 08:56:46","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":616322,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between anxiety scores and I/E ratios in women\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eNote:\u003c/strong\u003e As the DASS-21 is a short version of the original 42-item DASS form, to characterize the severity levels relative to the population, the scores on DASS-21 were multiplied by two.\u003c/p\u003e","description":"","filename":"Figure6.AnxietyscoresandIEratiosinwomen.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5844007/v1/4aff8ae538643541aec6b89c.jpeg"},{"id":74239066,"identity":"abb979d6-1405-4a42-bbc7-428cfefde40c","added_by":"auto","created_at":"2025-01-20 09:20:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":10359627,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5844007/v1/ec40d9fd-886e-4cac-9dd1-42f5f91bac19.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Higher Inhalation/Exhalation Ratio during Spontaneous Breathing Associates to Poor Mental Health in University Students","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eMental health problems are highly prevalent among university students [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], with depression, anxiety, and stress among the most common [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In 2018, it was reported that around 20% of university students in the United States experienced suicidal thoughts [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In a 2020 insight network survey across 10 universities in the UK, findings showed that \"1 in 5 students has a current mental health diagnosis,\" with \"almost half experiencing a serious psychological issue requiring professional help\"\u0026mdash;a rise from 1 in 3 in the 2018 survey [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. There was also an alarmingly high degree of students who have suffered from depressive disorders and anxiety problems in China [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Li Gao and colleagues (2020) conducted a meta-analysis by searching four electronic databases and selecting 113 studies, revealing an overall prevalence of depression among Chinese university students of 28.4%, with a 95% confidence interval of 25.7\u0026ndash;31.2% [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Gao and colleagues (2021) conducted a cross-sectional survey of 1,017 first-year Chinese university students, finding prevalence rates of anxiety and depression (ranging from mild to severe) at 40.3% and 45.3%, respectively [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. These mental health problems can lead to distress, poor academic performance, and lower job prospects after graduation [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Therefore, it is vital and urgent to improve the mental health of university students.\u003c/p\u003e \u003cp\u003ePractices such as intentional alteration of breathing patterns can positively influence certain mental states prior to pharmaceutical interventions. Two notable examples include abdominal breathing and breathing exercises with prolonged exhalation, both of which have demonstrated efficacy in improving mental health. Abdominal breathing is characterized by the movement of the diaphragm, which intentionally expands the abdominal wall [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The research found that abdominal breathing can reduce stress by lowering the pulse rate and blood pressure, improving vagal activity, and reducing the sympathetic reaction, offering a non-pharmacologic intervention to mitigate psychological stress [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Also, abdominal breathing has been associated with alleviating anxiety and depressive symptoms [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In addition, abdominal breathing has been shown to improve sustained attention, affect, and cortisol levels, indicating reduced stress and enhanced mental function in healthy individuals [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The phrenic nerve that innervates the functions of the diaphragm has a connection with the vagus nerve, which can affect the whole-body system [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Diaphragmatic motion in breathing, directly or indirectly, affects the sympathetic and parasympathetic nervous systems and also influences motor nerve activities and brain mass [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. These might be the basis of the influence of abdominal breathing on mental health. As for the breathing method with altered inhalation and exhalation duration, participants in a study reported increased relaxation, stress reduction, mindfulness, and positive energy when breathing with a low I/E ratio compared to a high I/E ratio [\u003cspan additionalcitationids=\"CR19 CR20\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The processes of inhalation and exhalation have distinct effects on the autonomic nervous system. During exhalation, the increased pressure in the chest cavity raises blood pressure, [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], which activates the aortic arch baroreceptors and increases the stimulation of the nucleus tractus solitarius. This, in turn, leads to increased excitation of parasympathetic efferent signals. Conversely, the effect of inhalation on sympathetic activity has a corresponding, reverse effect [\u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhile both breathing exercises exhibit the potential for alleviating mental health symptoms, the most suitable option remains unclear. Exploring the relationship between resting respiratory patterns (including I/E ratio and the contribution of abdominal movement to total respiratory movement) and mental health could aid psychologists in prescribing suitable breathing exercises.\u003c/p\u003e \u003cp\u003eA lot of research has been done on the relationship between mental health and resting respiratory patterns. The Trimodal Anxiety Questionnaire (TAQ) assesses anxiety in three dimensions: cognitive, physiological, and behavioral. The Self-Evaluation of Breathing Questionnaire (SEBQ) screens for faulty breath patterns. Jamie E. and colleagues found a positive correlation between TAQ and SEBQ (n\u0026thinsp;=\u0026thinsp;79, \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.49, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The limitation of this finding is that it did not show which breathing pattern is specifically associated with anxiety. Akae Kato and colleagues found that inhalation and exhalation durations were significantly shorter in both higher trait and higher state anxiety groups compared to the lower trait and lower state anxiety groups [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. However, this study did not investigate the I/E ratio. Also, this research enrolled 16 male participants, and the authors did not specify the number of participants in higher and lower anxiety categories. Therefore, larger sample sizes can help verify these findings and provide more information for further studies.\u003c/p\u003e \u003cp\u003eHence, the present study seeks to investigate the connection between resting respiration patterns (I/E ratio, abdominal movement contribution) and mental health among university students. Masaoka and colleagues found that, in the high-anxiety group, there were negative correlations between expiratory time and anxiety scores in both physical load and the noxious audio stimulation tests [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. In another experiment, Masaoka and colleague also found anticipatory anxiety (triggered by an electrical stimulus) decreases the expiratory duration, but not inspiration duration, in both low and high trait anxiety groups [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Therefore, we expect that people with higher levels of anxiety would display shorter exhalation durations during resting breathing and that people with lower levels of anxiety would display greater abdominal movement.\u003c/p\u003e"},{"header":"2 Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study design and participants\u003c/h2\u003e \u003cdiv id=\"Sec4\" class=\"Section3\"\u003e \u003ch2\u003e2.1.1 Study design\u003c/h2\u003e \u003cp\u003eThe current research is a cross-sectional study focusing on the relationship between university students\u0026rsquo; resting breathing patterns and their mental health. A total of 240 university students (120 of each sex, aged 18\u0026ndash;22) were recruited through random cluster sampling from the Physical Exercises course at Zhejiang University in September and October 2023. The procedure is outlined in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.1.2 Sample size estimation\u003c/h2\u003e \u003cp\u003eThe sample size was determined using G*Power version 3.1.9.7. Given that the primary statistical method was correlation analysis and the decision to analyze men and women separately, a medium effect size (Cohen\u0026rsquo;s ρ\u0026thinsp;=\u0026thinsp;0.30), a two-tailed significance level of 0.05, and a power of 0.90 were applied [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Based on these assumptions, 109 participants were needed. Accounting for a 10% drop-out rate, the required sample size was set at 120 participants for each sex.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.1.3 Sampling method\u003c/h2\u003e \u003cp\u003ePhysical exercises courses are mandatory for all students at Zhejiang University, but students can choose their preferred sporting activity within these courses. The available sports courses can be broadly categorized into six groups according to the character of the sports (e.g., football, basketball, and rugby were in one group of exercises). In total, there were 474 physical exercise classes, with approximately 30 students in each class. In order to obtain a representative sample, the current study randomly selected 18 classes, with three classes selected from each group of exercises. Students were recruited sequentially from each group of exercises until 20 students of each gender had been enlisted, reaching a total sample size of 240 students.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.1.4 Inclusion and exclusion\u003c/h2\u003e \u003cp\u003eThe inclusion criteria for participants were as follows: being 18\u0026ndash;22 years old; the absence of musculoskeletal or cardiorespiratory diseases; female participants taking the test on days 3\u0026ndash;10 after the end of menstruation; having providing written informed consent. The exclusion criteria included: recent or ongoing acute diseases without physical recovery; consumption of coffee or tea within 2 hours prior to the tests; and inability to perform 2 minutes of consecutively stable respiratory cycles. To minimize the effect of different time periods on students' physiological and psychological states, participants were required to perform the test from 8:00 to 12:00 on Saturdays and Sundays.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.1.5 Ethics and consent\u003c/h2\u003e \u003cp\u003e This study was conducted in accordance with the Declaration of Helsinki and approved by the Research Ethics Committee of Zhejiang University (Approval Number: 2023-039). All participants provided written informed consent and consented to use their clinical and demographic data for publication.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Measures\u003c/h2\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1 Respiratory testing and data processing.\u003c/h2\u003e \u003cp\u003eRespiratory belts (Vernier, Beaverton, OR, USA) were used to assess respiratory patterns. These belts were made of fabric with a resistive stretch sensor embedded in them and could be used to measure the respiration rate and breathing maneuvers. Two belts were employed for the current investigation: one was secured at the xiphoid process level and the other at the navel level to monitor the thoracic and abdominal motions, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The participants were instructed to sit quietly for 5 min before testing to ensure that they were mentally and physically calm. The subjects were asked to complete the test standing upright to eliminate the impact of abdominal circumference on the measurements. In accordance with the user guide, a researcher adjusted the straps until the lights on the belt turned green. During the test, the participants watched a neutral video on an 11-inch Xiaomi Pad (resolution:2560 \u0026times; 1600; Xiaomi, Beijing, China) that was placed 50\u0026ndash;80 cm in front of them to divert their attention from breathing. The respiration test lasted for 3 minutes.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWe observed that the respiration waves became more regular 30 seconds after the start of the test. Consequently, we took data from the 40th second to the 160th second (2 minutes in total) to calculate the breathing pattern. A MATLAB App Designer program (Matlab 2022a, Mathworks, Natick, MA, USA) was written to process the raw data and compute results.\u003c/p\u003e \u003cp\u003eTo calculate the respiration rate (RR), inhalation duration (ID), and exhalation duration (ED), the Kernel distribution (smoothing) was computed using the formula \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\widehat{f}}_{h}\\left(x\\right)=\\frac{1}{nh}\\sum\\:_{i=1}^{n}K\\left(\\frac{x-{x}_{i}}{h}\\right)\\)\u003c/span\u003e\u003c/span\u003e, for reducing the effect of noise. An h-value of 0.25 was empirically selected as the most appropriate. Then, code was written to find maximum values (peaks) where inspiration ended and minimum values (troughs) where expiration began. The inhalation duration (ID) was determined by subtracting the time of a peak from its preceding trough, and subsequently obtaining an average from the cumulative IDs (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Conversely, the exhalation duration (ED) was computed by subtracting the time of a trough from its preceding peak and averaging the totality of the accrued EDs. The I/E ratio was then derived by dividing ID by ED. The respiratory rate (per minute) was calculated by subtracting the time at which the first peak occurred from the time at which the last peak occurred, dividing it by the number of breaths taken in between to find the time for one breath, and finally dividing 60 by the time taken for one breath.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTo maintain as much data integrity as possible we used the raw data to calculate the thoracic and abdominal movements. This was done because the raw data does not affect the force values, whereas using smoothing processes would. Peaks and troughs were identified in their respective waveforms (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The force of the thoracic movement was determined by subtracting the average of all trough values from the average of all peak values for thoracic movement. Abdominal movements were calculated using an identical approach.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.2.2 Mental health testing\u003c/h2\u003e \u003cp\u003eThe 21-item Depression, Anxiety, and Stress Scales (DASS-21) were used to measure mental health indicators; 7 items for each scale (depression, anxiety, and stress) [\u003cspan additionalcitationids=\"CR33\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. The Chinese version of DASS-21 has been tested and confirmed to be a valid, reliable and effective tool for assessing depression, anxiety, and stress in adult residents of mainland China (Cronbach's α was 0.912; the mean inter-item correlation coefficient was 0.338; the test-retest Pearson correlation coefficient was 0.751.) [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The answers were reported on a four-point scale, from 0 (\u0026ldquo;did not apply to me at all\u0026rdquo;) to 3 (\u0026ldquo;applied to me very much, or most of the time\u0026rdquo;). As the DASS-21 is a short version of the original 42-item DASS form, to characterize the severity levels relative to the population, the scores on DASS-21 were multiplied by two and compared with the cutoff values of conventional severity labels. We divided DASS-21 scores into two symptom groups for anxiety (high\u0026thinsp;=\u0026thinsp;score\u0026thinsp;\u0026ge;\u0026thinsp;8, low\u0026thinsp;=\u0026thinsp;score\u0026thinsp;\u0026lt;\u0026thinsp;8), stress (high\u0026thinsp;=\u0026thinsp;score\u0026thinsp;\u0026ge;\u0026thinsp;15, low\u0026thinsp;=\u0026thinsp;score\u0026thinsp;\u0026lt;\u0026thinsp;15), and depression (high\u0026thinsp;=\u0026thinsp;score\u0026thinsp;\u0026ge;\u0026thinsp;10, low\u0026thinsp;=\u0026thinsp;score\u0026thinsp;\u0026lt;\u0026thinsp;10), according to previous studies [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this study, we calculated Cronbach's alpha coefficients (α) for stress (overall α\u0026thinsp;=\u0026thinsp;0.65; male α\u0026thinsp;=\u0026thinsp;0.64; female α\u0026thinsp;=\u0026thinsp;0.66), anxiety (overall α\u0026thinsp;=\u0026thinsp;0.76; male α\u0026thinsp;=\u0026thinsp;0.79; female α\u0026thinsp;=\u0026thinsp;0.72), and depression (overall α\u0026thinsp;=\u0026thinsp;0.69; male α\u0026thinsp;=\u0026thinsp;0.69; female α\u0026thinsp;=\u0026thinsp;0.69). The results indicated that the internal consistency of each psychological parameter was acceptable.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Statistical Analysis\u003c/h2\u003e \u003cp\u003eAt first, we tested the distribution of the data. Skewness and kurtosis scores indicated univariate normality: values for skewness were within the range of +/- 2 and kurtosis within the range of +/-7. [\u003cspan additionalcitationids=\"CR38\" citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. Homogeneity was checked with the Homogeneity of Variance Test. Then, the General Linear Model Univariate Test was used to compare the respiratory and psychological parameters between men and women, and to compare the respiratory patterns between low and high symptom groups of mental health. The level of significance was set at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.050. The effect sizes of the partial eta squared were interpreted as small (η\u0026sup2;p\u0026thinsp;=\u0026thinsp;0.01), medium (η\u0026sup2;p\u0026thinsp;=\u0026thinsp;0.06), and large (η\u0026sup2;p\u0026thinsp;=\u0026thinsp;0.14) [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBefore testing for correlation, the linearity was tested using linear regression. This was achieved by comparing the F-value generated from respiratory and psychological parameters with the F-value obtained from the squared respiratory parameters and psychological parameters. If the change in F-value was significant (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05), the relationship between the respiratory parameter and psychological parameter was quadratic; otherwise, the relationship was regarded as linear, as previously described [\u003cspan additionalcitationids=\"CR42\" citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]. Then, Pearson correlation was used for correlation analyses, and significance was set as \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.025 (Bonferroni correction).\u003c/p\u003e \u003c/div\u003e"},{"header":"3 Results","content":"\u003ch2\u003e3.1 Data description and comparison between\u0026nbsp;men and women\u003c/h2\u003e\n\u003cp\u003eOne male and two female participants had unnaturally forceful breathing, and one female student\u0026rsquo;s psychological questionnaire was missing. As a result, these participants were excluded, leaving a total of 119 male and 117 female participants. As shown in Table 1, there were significant differences in body height, weight, every respiration pattern parameter and the score of anxiety between male and female participants. Thus, we analyzed the data separately for each sex.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Data description and comparison between men and women.\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"553\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 117px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMen\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 119px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWomen\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAll parameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 38px;\"\u003e\n \u003cp\u003e\u003cstrong\u003en\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 79px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026plusmn;SD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 38px;\"\u003e\n \u003cp\u003e\u003cstrong\u003en\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 82px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u0026plusmn;SD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 47px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 10.1266%;\"\u003e\n \u003cp\u003eɳ\u0026sup2;p\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eAge (year)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e19.8\u0026plusmn;0.83\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e19.9\u0026plusmn;0.80\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e0.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e0.488\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eHeight(cm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e174\u0026plusmn;6.17\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e162\u0026plusmn;5.29\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e244\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e\u0026lt;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e0.510\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eWeight (kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e64.8\u0026plusmn;8.90\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e54.7\u0026plusmn;6.83\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e94.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e\u0026lt;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e0.289\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e21.4\u0026plusmn;2.47\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e20.8\u0026plusmn;2.32\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e3.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e0.053\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e.016\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e0.85\u0026plusmn;0.11\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e0.78\u0026plusmn;0.11\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e21.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e\u0026lt;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e0.085\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e0.41\u0026plusmn;0.14\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e0.35\u0026plusmn;0.11\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e15.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e\u0026lt;0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e0.062\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eDASS-Stress\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e11.1\u0026plusmn;5.88\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e11.6\u0026plusmn;5.71\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e0.510\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 156px;\"\u003e\n \u003cp\u003eDASS-Anxiety\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e7.83\u0026plusmn;4.65\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e9.18\u0026plusmn;5.09\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e4.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e0.035\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e0.019\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 156px;\"\u003e\n \u003cp\u003eDASS-Depression\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e119\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e6.34\u0026plusmn;6.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 82px;\"\u003e\n \u003cp\u003e6.80\u0026plusmn;5.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e0.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.3074%;\"\u003e\n \u003cp\u003e0.536\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 10.1266%;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eNotes: AM/(AM+TM), proportion of abdominal motion to the sum of abdominal and thoracic motions; BMI, body mass index; I/E ratio, ratio of inhalation duration to exhalation duration; ɳp\u0026sup2;, the partial eta squared.\u003c/p\u003e\n\u003ch2\u003e3.2 The comparison of the respiratory patterns between low and high symptom groups in men and woman\u003c/h2\u003e\n\u003cp\u003eWe categorized the DASS-21 scores into two symptom groups for anxiety (high: score \u0026ge; 8, low: score \u0026lt; 8), stress (high: score \u0026ge; 15, low: score \u0026lt; 15), and depression (high: score \u0026ge; 10, low: score \u0026lt; 10) based on previous studies\u0026nbsp;[35,36].\u0026nbsp;As shown in Table 2, women with high stress scores (n = 86) exhibited a lower I/E ratio than those with low stress scores (n = 31). In addition, we found no significant differences in solely inhalation duration and solely exhalation duration between low and high anxiety scores in women (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05), suggesting that women with higher stress scores tend to have relatively shorter inspiration and longer exhalation. Except for this finding, there were no significant differences in the other comparisons.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u0026nbsp;\u003c/strong\u003eThe comparison of the respiratory patterns between participants displaying low and high levels of mental health symptoms.\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"601\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRespiratory patterns\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLow\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003esymptoms scores\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHigh\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003esymptoms scores\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026eta;\u003csup\u003e2\u003c/sup\u003ep\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"9\" style=\"width: 77px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMen\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStress (n=87)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStress (n=32)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.85\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.84\u0026plusmn;0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.603\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.41\u0026plusmn;0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.42\u0026plusmn;0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e0.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.653\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnxiety(n=57)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnxious (n=62)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.85\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.85\u0026plusmn;0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.982\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.39\u0026plusmn;0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.43\u0026plusmn;0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e2.37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.127\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.020\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDepression (n=91)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDepression (n=28)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.85\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.85\u0026plusmn;0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e0.04\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.839\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.41\u0026plusmn;0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.44\u0026plusmn;0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e1.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.282\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.010\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"9\" style=\"width: 77px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWomen\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStress (n=86)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStress (n=31)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.79\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.74\u0026plusmn;0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e4.20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.043\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.035\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.35\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.34\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e0.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.555\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnxiety (n=47)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnxious (n=70)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.77\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.79\u0026plusmn;0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.351\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.008\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.35\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.35\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.925\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDepression (n=88)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDepression (n=29)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.79\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.75\u0026plusmn;0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e2.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.115\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.022\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 142px;\"\u003e\n \u003cp\u003e0.34\u0026plusmn;0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 139px;\"\u003e\n \u003cp\u003e0.36\u0026plusmn;0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 42px;\"\u003e\n \u003cp\u003e0.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.445\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 46px;\"\u003e\n \u003cp\u003e0.005\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eNotes: AM/(AM+TM), proportion of abdominal motion to the sum of abdominal and thoracic motions; I/E ratio, ratio of inhalation duration to exhalation duration; ɳp\u0026sup2;, the partial eta squared.\u003c/p\u003e\n\u003ch2\u003e3.3 The correlation between respiratory patterns and mental health in men and women\u003c/h2\u003e\n\u003cp\u003eAccording to the method for testing linearity, we found that the relations between every respiratory parameter and every psychological parameter were linear, thus Pearson correlational analysis was further applied.\u003c/p\u003e\n\u003cp\u003eThere was only one significant correlation between the I/E ratio and depression in women, as shown in Table 3. This correlation indicates that, for female university students (all enrolled women, n=117), those with higher depression scores tend to have a lower I/E ratio (i.e., relatively shorter inhalation and longer exhalation).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u003c/strong\u003e The correlation coefficients between respiratory patterns and mental health in all participants.\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"561\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMen\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 79px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWomen\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eAM/(AM+TM)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003eI/E ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eStress\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e119\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = 0.154\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.094\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = - 0.023\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.800\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = 0.021\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.824\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = -0.144\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.120\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAnxiety\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e119\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = 0.173\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.060\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = -0.112\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.226\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = -0.024\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.795\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = -0.124\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.185\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDepression\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 54px;\"\u003e\n \u003cp\u003e119\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = 0.166\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.071\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 79px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = -0.031\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.737\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 61px;\"\u003e\n \u003cp\u003e117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003c/em\u003e = -0.029\u003c/p\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e = 0.755\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 71px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003er\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;= -0.211\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ep\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;=\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e0.023\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003ch2\u003e3.4 The correlation between respiratory patterns and mental health in low and high symptom groups\u003c/h2\u003e\n\u003cp\u003eThen we stratified each sex into low and high symptom groups and tested the correlation between respiratory pattern and mental health. With respect to anxiety, for\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eboth men and woman in high anxiety symptom groups, the scores of anxiety and I/E ratios were significantly and negatively correlated (n = 62, \u003cem\u003er\u003c/em\u003e = -0.289, \u003cem\u003ep\u003c/em\u003e = 0.023); n = 70, r = -0.392, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001 for women), as shown in Figure 5 and 6. Due to the significant correlation between the body height and I/E ratios in women (n = 70, \u003cem\u003er\u003c/em\u003e = -0.298, \u003cem\u003ep\u003c/em\u003e = 0.012), we calculated the residuals of body height and I/E ratios and then tested the correlation of those residuals with the scores of anxiety. \u0026nbsp;The result of the correlation was \u003cem\u003er\u003c/em\u003e = -0.390, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, which indicated that the body height did not influence the correlation between I/E ratios and the anxiety scores.\u003c/p\u003e\n\u003cp\u003eBoth stress and depression were not significantly correlated with respiratory patterns for both men and women, in neither the low symptom or high symptom group (\u003cem\u003er\u003c/em\u003e \u0026lt; 0.20, \u003cem\u003ep\u003c/em\u003e \u0026gt; 0.05).\u0026nbsp;\u003c/p\u003e"},{"header":"4 Discussion","content":"\u003cp\u003eThe aim of the current study was to test the relationship between mental health (stress, anxiety, and depression) and resting respiratory patterns (I/E ratio and (AM/(AM\u0026thinsp;+\u0026thinsp;TM)), which could assist professionals in recommending appropriate breathing exercises for managing mental issues in university students. A significant negative correlation between anxiety scores and I/E ratios among students with high anxiety symptoms was observed and evident in both men and women. Besides, the I/E ratio was significantly higher in women in the low stress symptom category than in those in the high stress symptom category, but no substantial correlations between I/E and stress were observed. In addition, female students with lower depression scores tend to exhibit a smaller I/E ratio, characterized by relatively shorter inhalations and longer exhalations.\u003c/p\u003e \u003cp\u003eThe negative correlation between anxiety and I/E ratio in students displaying elevated anxiety symptoms is contrary to what we expected. Studies found that during prolonged expiratory breathing, parasympathetic nervous function was significantly activated [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e], and the elevated parasympathetic nervous function promoted relaxation [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. Thus, people with lower I/E ratios were expected to be more relaxed. There could be two possible explanations for our observation. At first, the shortened exhalation duration triggered by the noxious audio stimulation (anticipatory anxiety) cannot indicate a shorter exhalation during resting breathing for anxious people, referring to the studies conducted by Masaoka and Homma [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Secondly, the relationship between anxiety levels and the I/E ratio during spontaneous breathing may differ from the relationship observed during controlled breathing, referring to previous researches [\u003cspan additionalcitationids=\"CR19 CR20\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. We suggest that the observed resting respiratory pattern (shorter inhalation combining longer exhalation) might be an autonomically compensatory strategy to cope with anxiety, similarly to \u0026ldquo;sighing\u0026rdquo;.\u003c/p\u003e \u003cp\u003eSighing seems to act as a psychophysiological reset mechanism, restoring homeostatic balance when it has been compromised [\u003cspan additionalcitationids=\"CR47 CR48\" citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]. In humans, sighs were reported to be associated with anxiety, fear and resentment [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. Compared to healthy controls, individuals reporting relatively high anxiety sensitivity, suffering from chronic anxiety exhibit more frequent sighing than healthy individuals under rest or stress conditions [\u003cspan additionalcitationids=\"CR52\" citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e]. Sighing is characterized by deep breaths followed by extended, relatively longer exhales [\u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e54\u003c/span\u003e], from which it can be deduced that relatively longer exhalation duration in sighing can decrease the level of anxiety. Sighing restores lung compliance and gas exchange efficiency and reduces hypoxia and hypercapnia [\u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e55\u003c/span\u003e], while the resting respiration pattern with relatively shorter inhalation duration and longer exhalation duration might also has these effects. Respiratory changes in response to anxiety are affected by higher centres related to the emotion [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]. Stimulation of the amygdala produces a rapid increase in respiratory rate followed by a feeling of fear and anxiety [\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e]. The piriform cortex may produce rhythms, and the piriform\u0026ndash;amygdala complex may alter respiratory rhythm in response to qualitative changes in emotions [\u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e]. These brain structures may be associated with changes in breathing patterns when coping with anxiety.\u003c/p\u003e \u003cp\u003eA significantly higher I/E ratio in women with low stress symptoms (n\u0026thinsp;=\u0026thinsp;86) compared to those with high stress symptoms (n\u0026thinsp;=\u0026thinsp;31) supports the negative correlation between the I/E ratio and anxiety scores as presented above. The current study is only a preliminary exploration of the topic. There were only 31 female participants in the high stress symptom category. Future studies may enroll more participants who have high stress symptom to verify our results. Additionally, as our sample size of participants displaying elevated depression symptoms was quite small (n\u0026thinsp;=\u0026thinsp;29), future studies can also enroll more participants in this category.\u003c/p\u003e \u003cp\u003eIn addition, our study found that the correlation between the I/E ratio and mental health is stronger in women than in men. The results in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e showed that men generally exhibited better mental health than women, particularly concerning anxiety, which was consistent with findings from other studies [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e]. Additionally, we observed that men's I/E ratio was higher than that of women, in line with our previous research [\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e59\u003c/span\u003e]. Thus, we suggest that the stronger correlation may be attributed to the more severe mental symptoms experienced by women.\u003c/p\u003e"},{"header":"5 Limitations","content":"\u003cp\u003eThis is preliminary research. We randomly enrolled participants and found that the population with high stress scores and high depression scores was not substantial. Future studies may enroll more participants who have high stress scores and/or high depression scores.\u003c/p\u003e"},{"header":"6 Conclusions","content":"\u003cp\u003eIn general, university students who exhibit relatively longer inhalation and shorter exhalation tend to have better mental health, especially among women. This respiratory pattern may represent an autonomic compensatory strategy to cope with psychological distress. More attention could be devoted to breathing exercises involving altered I/E ratios for mental health management.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgments\u003c/p\u003e\n\u003cp\u003eThe authors sincerely thank all the participants. Special thanks to Yu-Xuan Ouyang, Yi-Wen Xi, Hua-Yang Fan, Yan Zhang, Jia-Xiang He, Xi-Ya Sun, and Xuan-Xue He for data collection, and to Xie Zeng for making Figure 2.\u003c/p\u003e\n\u003cp\u003eAuthor Contributions\u003c/p\u003e\n\u003cp\u003eOR, WL, YD, KJ, IT, JX, FR, and IG contributed to the conceptualization and methodology. YD, KJ, WL, and AH contributed to data collection and processing. WL and IT contributed to the formal analysis. WL, KJ, and YD wrote the original draft; YD, OR, IG, IT, AH, JX, and FR reviewed and edited the manuscript. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003eFunding:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWenming Liang and Jing Xiao was funded by the Capital\u0026rsquo;s Funds for Health Improvement and Research (2022-2-4175) in China. Wenming Liang was also funded by Jimei University in China and Vilnius University in Lithuania; Yinling Du was funded by Hangzhou Normal University, China; Kai Jiang was funded by Zhejiang University, China.\u003c/p\u003e\n\u003cp\u003eData Availability Statement\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available on request from the corresponding author\u0026nbsp;Yin-Ling Du.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eThis study was conducted in accordance with the Declaration of Helsinki and approved by the Research Ethics Committee of Zhejiang University (Approval Number: 2023-039). All participants provided written informed consent and consented to use their clinical and demographic data for publication.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eDeclaration of interests\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKetchen Lipson, S.; Gaddis, S.M.; Heinze, J.; Beck, K.; Eisenberg, D. Variations in Student Mental Health and Treatment Utilization Across US Colleges and Universities. \u003cem\u003eJ Am Coll Health\u003c/em\u003e \u003cstrong\u003e2015\u003c/strong\u003e, \u003cem\u003e63\u003c/em\u003e, 388\u0026ndash;396, doi:10.1080/07448481.2015.1040411.\u003c/li\u003e\n\u003cli\u003eBeiter, R.; Nash, R.; McCrady, M.; Rhoades, D.; Linscomb, M.; Clarahan, M.; Sammut, S. 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Respiratory Patterns and Physical Fitness in Healthy Adults: A Cross-Sectional Study. \u003cem\u003eBMC Public Health\u003c/em\u003e \u003cstrong\u003e2024\u003c/strong\u003e, \u003cem\u003e24\u003c/em\u003e, 228, doi:10.1186/s12889-024-17687-8.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-psychology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"psyo","sideBox":"Learn more about [BMC Psychology](http://bmcpsychology.biomedcentral.com/)","snPcode":"","submissionUrl":"","title":"BMC Psychology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"inhalation/exhalation ratio, abdominal movement, stress, anxiety, depression","lastPublishedDoi":"10.21203/rs.3.rs-5844007/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5844007/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e \u003cp\u003eBreathing exercises, particularly those involving altered inhalation/exhalation duration ratios (I/E ratios) and increased abdominal movement, have demonstrated the potential for alleviating symptoms of mental health issues. However, it remains unclear which approach is more effective. This study aims to examine how resting respiratory patterns (e.g., I/E ratios and abdominal movement) relate to mental health, potentially guiding psychologists in recommending tailored breathing exercises.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eA total of 240 university students (120 male and 120 female) were recruited by systematic sampling. The I/E ratio and the contribution of abdominal movement to the sum of abdominal and thoracic movements AM/(AM\u0026thinsp;+\u0026thinsp;TM) were recorded by respiration belts, while depression, anxiety, and stress levels were assessed with the DASS-21. Data were analyzed for each gender; each gender being categorized into either a low or high level symptom category.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003eWomen with high stress symptoms exhibited significantly lower I/E ratios (a lower I/E ratio indicates breathing with relatively shorter inhalation and longer exhalation) compared to those with lower stress symptoms (n\u0026thinsp;=\u0026thinsp;117, \u003cem\u003eF\u003c/em\u003e\u0026thinsp;=\u0026thinsp;4.198, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.043, ηp\u0026sup2; = 0.035). A negative correlation was observed between I/E ratios and depression in women (n\u0026thinsp;=\u0026thinsp;117, \u003cem\u003er\u003c/em\u003e = -0.211, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.023). For students with high anxiety symptoms, I/E ratios were negatively correlated with anxiety scores in both men (n\u0026thinsp;=\u0026thinsp;61, \u003cem\u003er\u003c/em\u003e = -0.292, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.022) and women (n\u0026thinsp;=\u0026thinsp;70, \u003cem\u003er\u003c/em\u003e = -0.392, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There were no substantial correlations between abdominal movement and mental health.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusions\u003c/b\u003e\u003c/p\u003e \u003cp\u003eIn general, university students who exhibit relatively shorter inhalations and longer exhalations tend to have poorer mental health, especially among women; This respiratory pattern may represent an autonomic compensatory strategy for coping with psychological distress. More attention could be devoted to breathing exercises involving altered I/E ratios as part of mental health management programs.\u003c/p\u003e","manuscriptTitle":"Higher Inhalation/Exhalation Ratio during Spontaneous Breathing Associates to Poor Mental Health in University Students","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-20 08:56:41","doi":"10.21203/rs.3.rs-5844007/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-11-21T10:58:30+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-29T13:44:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"73291855947505173990475385951310015603","date":"2025-05-20T01:44:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"281453099041295776299121655395405970110","date":"2025-05-15T13:59:04+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-05-09T10:46:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"4667025975738606993031029822100120550","date":"2025-05-01T17:12:07+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-26T14:52:39+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-04-01T11:23:07+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-01-23T08:15:43+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-01-17T11:30:20+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Psychology","date":"2025-01-16T17:58:26+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-psychology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"psyo","sideBox":"Learn more about [BMC Psychology](http://bmcpsychology.biomedcentral.com/)","snPcode":"","submissionUrl":"","title":"BMC Psychology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9e47c97f-464c-4a0e-b328-f263f64dd4c7","owner":[],"postedDate":"January 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-09T04:53:44+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-20 08:56:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5844007","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5844007","identity":"rs-5844007","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}