Isotemporal substitution analysis of time between sleep, sedentary behavior, and physical activity on depressive symptoms in older adults: a cross-sectional study

ABSTRACT BACKGROUND: Compared to young individuals, older adults participate more in sedentary behavior (SB) and less in physical activity (PA). These behaviors are associated with numerous adverse health factors. OBJECTIVE: The purpose of the study was to examine the hypothetical effects of substituting time spent sleeping, performing SB, and performing moderate-to-vigorous physical activity (MVPA) on depressive symptomatology in older adults. DESIGN AND SETTING: An analytical cross-sectional study employing exploratory survey methods was conducted in the city of Alcobaça in the state of Bahia, Brazil METHODS: The study included 473 older adults who answered a structured questionnaire during an interview. Exposure time to SB and PA level were assessed using the International Physical Activity Questionnaire, and depressive symptoms were analyzed using the short version of the Geriatric Depression Scale. An isotemporal replacement model was used to evaluate the effects of different SB sessions on depressive symptomatology. RESULTS: An increase in the risk of depressive symptoms was observed when MVPA and sleep time were substituted for the same SB time at all times tested, with maximum values of 40% and 20%, respectively. Opposite substitution of MVPA and sleep time increments reduced the risk of depressive symptomatology by 28% and 17%, respectively. CONCLUSIONS: The results of the present study indicate that replacing SB with the same amount of sleep or MVPA may reduce depressive symptoms. The longer the reallocation time, the greater are the benefits.

Establishment of an intervention model for adolescent obesity based on component isochronous substitution method / 中国学校卫生

Objective@#To explore the relationship between isochronous substitution and BMI, waist circumference (WC), and body fat rate (FAT) among physical activity (PA), sedentary (SB), and sleep (SLP), so as to provide effective measures for obesity control in adolescents.@*Methods@#A total of 193 adolescents aged 12-15 (90 males and 103 females) was randomly selected, and their height, weight, and BMI were measured using routine testing methods from May to August 2022. The PA, SB and SLP of the participants were measured using a 3D accelerometer (ActiGraph GT3X+).@*Results@#The arithmetic mean value overestimated SLP (40.8%) and SB (39.6%) to some extent, and underestimated LPA (16.1%) and MVPA (3.5%) to some extent. Based on the ISM at 15 min, MVPA was substituted for other activity, BMI Z decreased by 0.17-0.22 units, WC Z decreased by 0.16-0.20 units, and FAT Z decreased by 0.17-0.22 units. The substitution between MVPA and for other activity exhibited significant asymmetry. The effects of MVPA substitutions for SB was the largest, followed by the effects of MVPA substitutions for SLP, and the effects of MVPA substitutions for LPA was the lowest. As MVPA substitutions for other behaviors, it reached its maximum (0.06-0.08 units ) when the MVPA time increased by 5 minutes.@*Conclusions@#MVPA plays an irreplaceable role in the control of adolescent obesity . While reducing SB time, MVPA duration should be increased to ensure that the daily MVPA duration is not less than 55 minutes in order to effectively control obesity.

Component analysis of relationship between 24 hour movement behavior and physical fitness in college students / 中国学校卫生

Objective@#To explore the relationship between 24 hour movement behavior and physical fitness in college students, so as to provide a reference for physical fitness interventions for college students.@*Methods@#A survey was conducted from September 23 to November 12, 2022, involving 342 college students selected from one comprehensive college among Shanghai City, Hubei Province and Zhejiang Province. Accelerometers were used to measure 24 hour movement behavior, and programs specified in the National Physical Fitness Standards for Students (2014 revision) were used to evaluate physical fitness. Compositional linear regression was used to analyze the association between 24 hour movement behavior and physical fitness. The effects of compositional isotemporal substitution of 24 hour movement behavior on physical fitness were also examined.@*Results@#The geometric means for sleep, sedentary behavior, light physical activity (LPA), and moderate to vigorous physical activity (MVPA) were 515.89, 678.88 , 196.30, 48.92 min/d, respectively, and the comprehensive physical fitness score was (73.09±8.55). The proportion of participants who passed the fitness test was 72.51%. Overall, 20.76% had excellent or good scores, whereas 6.73% failed. Compositional linear regression indicated that physical fitness was significantly positively associated with MVPA ( β =2.55) and LPA ( β = 5.88 )( P <0.05), but no significantly associated with sleep ( β =-5.18) and sedentary behavior ( β =-3.24)( P >0.05). Isotemporal substitution indicated that reallocation of 15 minutes from sleep and sedentary behavior to MVPA resulted in a 0.71 and 0.64 point increase in physical fitness, respectively. Similarly, reallocating the same duration to LPA led to a 0.50 and 0.43 point increase in physical fitness, respectively. Dose response analysis revealed that the mutual substitution of LPA with sedentary behavior and sleep had symmetry, whereas the mutual substitution of MVPA with sedentary behavior and sleep had asymmetry. The effectiveness of replacing sleep or sedentary behavior with MVPA in improving physical fitness decreased with increasing allocation time, whereas the adverse effects of replacing MVPA with sleep or sedentary behavior increased with increasing allocation time.@*Conclusion@#In the context of 24 hour movement behavior, increasing the time spent on LPA and MVPA is beneficial for physical fitness among college students. It should be recommend that college students actively transition from sedentary behavior to engaging in physical activity, with a particular emphasis on incorporating MVPA.

The relationship between behavior isotemporal substitution and depression among vocational school students with different moderate-to-vigorous physical activity durations / 中国学校卫生

Objective@#To explore the relationship between isotemporal substitution of 10 min/d of vigorous physical activity (VPA), moderate physical activity (MPA), walking, sedentary behavior (SB) and sleep (SLP) and depression among vocational school students with different duration of moderate-to-vigorous physical activity (MVPA), so as to provide time allocation suggestions for reducing depression levels.@*Methods@#The convenient cluster sampling method was adopted to conduct a questionnaire survey among 8 149 grade one to grade three students in 14 vocational schools in Shanghai and Jiangsu Province from December 2021 to January 2022. According to whether the MVPA reached 60 min/d, the vocational school students were divided into the MVPA standard group and the MVPA non-standard group, and the isotemporal substitution model was used for analysis.@*Results@#About 19.81% of students were in the MVPA standard group. In the MVPA non-standard group, substituting MPA for all other studied behaviors and substituting SLP for walking and SB were negatively correlated with depression ( β =-0.78, -0.90, -0.88, -0.83; -0.07 , -0.05, P <0.05), and the association of MPA substitution was much greater than that of SLP substitution. In the MVPA standard group, replacing VPA, walking and SB with SLP were all negatively associated with depression ( β =-0.23, -0.12, -0.10 ), whereas replacing MPA, SB and SLP with VPA was all positively associated with depression ( β =0.15, 0.13, 0.23) ( P <0.05).@*Conclusion@#The MVPA level of vocational school students is low. The effects of isotemporal substitution for VPA and MPA are different when MVPA duration is up to standard and when MVPA duration is not up to standard. Appropriate time allocation suggestions should be provided based on the characteristics of adolescents with different MVPA durations.

The isochronous substitution effect of 24 hour activity behavior on physical health of college students / 中国学校卫生

Objective@#An isochronous substitution model was established to explore the association and substitution effect between college students 24 hour activity behavior and physical health, so as to provide specific activity behavior suggestions for college students to improve their physical health.@*Methods@#A stratified random cluster sampling method was used to conduct physical fitness tests and 24 hour activity behavior surveys among 2 794 college students in 12 colleges and universities in Tianjin.Time spent on sedentary behavior(SB), light intensity physical activity(LPA), moderate to vigorous physical activity(MVPA) and sleep(SLP) time. The isochronous method of components was used to explore the relationship between 24 h activity behavior and physical health.@*Results@#Except for 50 m running, MVPA was negatively correlated with BMI Z ( β =-0.62, P <0.05), but positively correlated with other physical fitness indexes ( β =0.34~274.23, P <0.05). LPA was not associated with lung capacity, sitting forward flexion and 50 m running, and negatively correlated with other physical fitness indexes ( β =-14.30- -0.19, P <0.05). SB was negatively correlated with most physical fitness indexes ( β =-11.57- -0.33, P <0.05), but positively correlated with BMI Z ( β =0.45, P < 0.05 ). In addition to lung capacity, SLP was positively correlated with BMI Z , total physical fitness score,1 minute sit-ups, pull ups, 800/1 000 m running, sitting forward flexion, and 50 m running ( β =0.27-11.21, P <0.05), but negatively correlated with long jump ( β =-0.10, P <0.05）. Isochronous substitution showed that the adverse effects of 30 min/d SB and LPA substitution of MVPA were much greater than the beneficial effects of MVPA substitution for corresponding behaviors (total physical score: SB, -0.58 vs 0.47 points; LPA, -0.50 vs 0.38 points).@*Conclusion@#MVPA and SLP have been found to have a positive effect on physical fitness among college students. Therefore, in the process of improving the physical health of college students, ensuring adequate sleep, improving MVPA and reducing SB as much as possible may be one of the effective methods.

Relationship between 24 hour movement behavior and obesity indicators in children and adolescents / 中国学校卫生

Objective@#The method of compositional data analysis was used to explore the relationship between 24 hour movement behavior and obesity indicators, and to examine the difference of quantitative effect on obesity indicators when one behavior replaced another behavior, so as to provide specific movement behavior advice for weight control in children and adolescents.@*Methods@#In June 2021, 231 students from eight classes in a primary school and a middle school in Taiyuan City, Shanxi Province were voluntarily recruited by using random cluster sampling. ActiGraph GT3X+ accelerometer was used to measure 24 hour movement behavior and Inbody J20 body composition analyzer was used to measure body composition. The relationship between each component and obesity indicators was analyzed by compositional multivariate linear regression model. In addition, 30 minutes of one behavior was used to replace another behavior to predict the effect difference of the outcomes.@*Results@#After adjusting for covariates such as height, weight, age, and sex, compared with time spent in sedentary behavior(SB), sleep (SLP) and light physical activity (LPA), time spent on moderate to vigorous physical activity (MVPA) was positively correlated with fat free mass index (FFMI) ( β= 0.40, P ＜0.05), negatively correlated with waist circumference (WC) ( β=-2.50, P ＜0.05) and waist hip ratio (WHR) ( β= -0.04 , P ＜0.05). Compared with SB, SLP and MVPA, time spent on LPA was positively correlated with WHR ( β=0.06, P < 0.05 ). If MVPA of 30 min/d replaces SLP, SB, and LPA respectively, WC and WHR decrease 1.10,1.10,1.34 cm and 0.02, 0.02 ,0.02 respectively, and FFMI increases 0.19,0.19,0.15 kg/m 2 respectively.@*Conclusion@#In 24 h movement behavior, with consistent level of sedentary behavior, sleep or low intensity movement behavior, maintaining a high level of MVPA and replacing sedentary with active activities are crucial for optimal abdominal fat and fat free mass in children and adolescents.

Relationship between 24 hour movement behavior and physical fitness among pupils / 中国学校卫生

Objective@#To examine the relationship between 24 hour movement behavior and physical fitness of pupils by using compositional analyses, so as to provide a theoretical basis for physical activity promotion and physical fitness improvement.@*Methods@#By random cluster sampling method, 120 students of grade 4 and 5 from the Second Experimental Primary School of Yingze District of Taiyuan were selected. Physical fitness was evaluated by the indicators of the Protocol of National Physical Training Standard and 20 meter shuttle run. The movement behavior was measured by accelerometer. The relationship between each behavior and physical fitness was analysed by component multiple linear regression, and the effect of replacement of components on physical fitness was discussed.@*Results@#Girls 1minute situps were lower than boys（24.79±7.77，28.21±6.52），and sitting forward flexion was higher than boys[9.00（5.00，14.00），5.20（1.00，9.75）cm]（ t/Z =2.60，-3.15， P ＜0.05）. Boys showed higher light physical activity(LPA), moderate to vigorous physical activity(MVPA) and lower sedentary behavior(SB), while girls showed lower LPA, MVPA and higher SB. MVPA was positively correlated with the performance of 30 second rope skipping and 20 meter shuttle run ( β= 13.19, 7.90, P <0.05). Sleep(SLP), SB, and LPA were not significantly correlated with physical fitness. After re allocating 10 min MVPA to SB and SLP，the performance of 30 second rope skipping and 20 meter shuttle run increased by 2.25，2.28 and 1.28 ,1.34 times，respectively，while significantly decreased after reverse reallocation ( P <0.05). MVPA replaced LPA，the 20 meter shuttle run performance increased 1.46 times，while decreased significantly in reverses ( P <0.05).@*Conclusion@#MVPA is positively correlated with the speed and endurance of pupils. There are gender differences in movement behavior patterns and physical fitness. Children, especially girls, should be encouraged to raise exercise awareness and increase PA, especially MVPA.

Isotemporal substitution of sedentary time with physical activity and its associations with mental health of Japanese office workers / 体力科学

In this study, we performed isotemporal substitution analysis to examine potential associations of sedentary time and physical activity with mental health of Japanese office workers. This study employed a cross-sectional study design. We analyzed data on 108 Japanese office workers (mean age 46.4 ± 9.8 years; 64.8% women) in the study. Sedentary behavior (SB; ≤ 1.5 metabolic equivalents [METs]), light-intensity physical activity (LPA; 1.6–2.9 METs), and moderate-to-vigorous physical activity (MVPA; ≥ 3 METs) were measured with a triaxial accelerometer. Two kinds of self-administered questionnaires, the mental stress (K6) and work engagement (Utrecht Work Engagement Scale), were used to assess negative/positive mental health. A cut-off score of 5 or higher on the K6 was used to define persons with mental stress. Logistic and multiple regression analyses using an isotemporal substitution model was applied to demonstrate the association between replacing 30 min/d of SB with an equal amount of time spent on LPA or MVPA and mental stress and work engagement; the studied covariates were age, sex, body mass index, economic status, education, and overtime hours. The results showed that replacing SB with MVPA for 30 min/d was significantly decreased odds ratio (OR) of mental stress (OR = 0.38, 95% confidence interval 0.15–0.92), whereas the replacement was not associated with work engagement (B = 0.16, P = 0.38). In contrast, substitution of SB with LPA was not associated with mental stress and work engagement. These results indicate that substituting sedentary time with MVPA could be associated with mental stress of Japanese office workers.