Associations of daily sedentary behavior,physical activity,and sleep with irritable bowel syndrome:A prospective analysis of 362,193 participants

Background:Irritable bowel syndrome(IBS)substantially affects quality of life and requires early prevention.This study aimed to elucidate the relationships between IBS and daily behaviors,including sedentary behavior(SB),physical activity(PA),and sleep.In particular,it seeks to identify healthy behaviors to reduce IBS risk,which previous studies have rarely addressed.Methods:Daily behaviors were retrieved from self-reported data of 362,193 eligible UK Biobank participants.Incident cases were determined by self-report or health care data according to RomeⅣcriteria.Results:A total of 345,388 participants were IBS-free at baseline,during a median follow-up of 8.45 years,19,885 incident IBS cases were recorded.When examined individually,SB and shorter(≤7 h/day)or longer(>7 h/day)sleep duration were each positively associated with increased IBS risk,and PA was associated with lower IBS risk.The isotemporal substitution model suggested that replacing SB with other activities could provide further protective effects against IBS risk.Among people sleeping≤7 h/day,replacing 1 h of SB with equivalent light PA,vigorous PA,or sleep was associated with 8.1%(95%confidence interval(95%CI):0.901-0.937),5.8%(95%CI:0.896-0.991),and 9.2%(95%CI:0.885-0.932)reduced IBS risk,respectively.For people sleeping>7 h/day,light and vigorous PA were associated with a 4.8%(95%CI:0.926-0.978)and a 12.0%(95%CI:0.815-0.949)lower IBS risk,respectively.These benefits were mostly independent of genetic risk for IBS.Conclusion:SB and unhealthy sleep duration are risk factors for IBS.A promising way to mitigate IBS risk for individuals sleeping≤7 h/day and for those sleeping>7 h/day appears to be by replacing SB with adequate sleep or vigorous PA,respectively,regardless of the genetic predisposition of IBS.

Relationships among Sedentary Time,Electronic Product Addiction,and Depression in Adolescents during the COVID-19 Epidemic:A Cross-Lagged Study

Objective:This study was conducted to explore the relationships among sedentary behavior(SB),electronic product addiction(EPA),and depression(D)in adolescents during the COVID-19 epidemic.Methods:A total of 604 adolescents(including 309 girls and 295 boys aged 12-18)were selected from Qufu City,Shandong Province,China for three rounds of investigation.The model was constructed using AMOS 23.0 software,and cross-lagged analysis was conducted.Results:SB at T1 can significantly positively predict SB and EPA at T2(p<0.05).EPA at T1 can significantly positively predict SB and D at T2(p<0.05).Physical activity level and SB at T2 can significantly predict SB and EPA at T3(p<0.05).EPA at T2 can significantly predict SB,EPA,and D at T3(p<0.05).Conclusions:SB and EPA are predictive factors for D.Moreover,SB can significantly positively predict D and indirectly predict D through the mediating effect of EPA.

Predictive Modeling of Sedentary Behavior Patterns in Adults Using Stacked LSTM

A new health concern in recent periods has seen the evolution of uncertain sedentary behavior.Remaining sedentary for extended durations is regarded as a notable hazard across various adult age brackets,especially the excessive dependence on automobiles for transportation.Throughout the active period,monitoring seating habits has been made easier by sensors.Nevertheless,there exists a disagreement among professionals regarding the most suitable quantifiable criteria for encompassing the comprehensive data on sedentary behavior throughout the day.Owing to variations in measurement methodologies,data analysis approaches,and the lack of essential outcome indicators such as the total sedentary duration,the assessment of sedentary patterns in numerous research investigations was considered unfeasible.The research suggested fleeting granularity distinguish occurrences of regular human activities.Sophisticated units(essential cells) acquire multivariate transitory information.Frequent Behavior Patterns(FBPs) can be identified with a estimation of timeframe using our proposed scalable algorithms that employ collected widespread multivariate data(fleeting granularity).The research outcome,supported by rigorous analyses on two validated datasets,mark a significant progression.In the final stages of the study,a stacked Long Short-Term Memory(LSTM) model was utilized to replicate and forecast repetitive sedentary behavior patterns,leveraging data from the preceding six-hour window blocks of sedentary activity.The model effectively replicated state traits,previous action sequences,and duration,attaining an impressive 99% accuracy level as assessed through RMSE,MSE,MAPE,and r-correlation metrics.

Replacement of leisure-time sedentary behavior with various physical activities and the risk of dementia incidence and mortality:A prospective cohort study

Background:Whether or not there is targeted pharmacotherapy for dementia,an active and healthy lifestyle that includes physical activity(PA)may be a better option than medication for preventing dementia.We examined the association between leisure-time sedentary behavior(SB)and the risk of dementia incidence and mortality.We further quantified the effect on dementia risk of replacing sedentary time with an equal amount of time spent on different physical activities.Methods:In the UK Biobank,484,169 participants(mean age=56.5 years;45.2%men)free of dementia were followed from baseline(2006-2010)through July 30,2021.A standard questionnaire measured individual leisure-time SB(watching TV,computer use,and driving)and PA(walking for pleasure,light and heavy do-it-yourself activity,strenuous sports,and other exercise)frequency and duration in the 4 weeks prior to evaluation.Apolipoprotein E(APOE)genotype data were available for a subset of 397,519(82.1%)individuals.A Cox proportional hazard model and an isotemporal substitution model were used in this study.Results:During a median 12.4 years of follow-up,6904 all-cause dementia cases and 2115 deaths from dementia were recorded.In comparison to participants with leisure-time SB<5 h/day,the hazard ratio((HR),95%confidence interval(95%CI))of dementia incidence was 1.07(1.02-1.13)for 5-8 h/day and 1.25(1.13-1.38)for>8 h/day,and the HR of dementia mortality was 1.35(1.12-1.61)for>8 h/day.A 1 standard deviation increment of sedentary time(2.33 h/day)was strongly associated with a higher incidence of dementia and mortality(HR=1.06,95%CI:1.03-1.08 and HR=1.07,95%CI:1.03-1.12,respectively).The association between sedentary time and the risk of developing dementia was more profound in subjects<60 years than in those>60 years(HR=1.26,95%CI:1.00-1.58 vs.HR=1.21,95%CI:1.08-1.35 in>8 h/day,p for interaction=0.013).Replacing 30 min/day of leisure sedentary time with an equal time spent in total PA was associated with a6%decreased risk and 9%decreased mortality from dementia,with exercise(e.g.,swimming,cycling,aerobics,bowling)showing the strongest benefit(HR=0.82,95%CI:0.78-0.86 and HR=0.79,95%CI:0.72-0.86).Compared with APOEε4 noncarriers,APOEε4 carriers are more likely to see a decrease in Alzheimer’s disease incidence and mortality when PA is substituted for SB.Conclusion:Leisure-time SB was positively associated with the risk of dementia incidence and mortality.Replacing sedentary time with equal time spent doing PA may be associated with a significant reduction in dementia incidence and mortality risk.

Physical Activity,Sedentary Behavior,and the Risk of Cardiovascular Disease in Type 2 Diabetes Mellitus Patients:The MIDiab Study

The aim of this study was to explore the associations of moderate-to-vigorous-intensity physical activity(MVPA)time and sedentary(SED)time with a history of cardiovascular disease(CVD)and multifactorial(i.e.,blood pressure(BP),body mass index(BMI),low-density lipoprotein cholesterol(LDL-C),and glycated hemoglobin A1c(HbA1c))control status among type 2 diabetes mellitus(T2DM)patients in China.A cross-sectional analysis of 9152 people with type 2 diabetes from the Multifactorial Intervention on Type 2 Diabetes(MIDiab)study was performed.Patients were grouped according to their self-reported MVPA time(low,<150 min·week−1;moderate,150 to<450 min·week−1;high,≥450 min·week−1)and SED time(low,<4 h·d–1;moderate,4 to<8 h·d–1;high,≥8 h·d–1).Participants who self-reported a history of CVD were identified as having a CVD risk.Odds ratios(ORs)and 95%confidence intervals(CIs)of CVD risk and multifactorial control status associated with MVPA time and SED time were estimated using mixed-effect logistic regression models,adjusting for China’s geographical region characteristics.The participants had a mean±standard deviation(SD)age of(60.87±8.44)years,44.5%were women,and 25.1%had CVD.After adjustment for potential confounding factors,an inverse association between high MVPA time and CVD risk that was independent of SED time was found,whereas this association was not observed in the moderate-MVPA group.A higher MVPA time was more likely to have a positive effect on the control of BMI.Compared with the reference group(i.e.,those with MVPA time≥450 min·week−1 and SED time<4 h·d–1),CVD risk was higher in the low-MVPA group:The OR associated with an SED time<4 h·d–1 was 1.270(95%CI,1.040–1.553)and that associated with an SED time≥8 h·d–1 was 1.499(95%CI,1.149–1.955).We found that a high MVPA time(i.e.,≥450 min·week−1)was associated with lower odds of CVD risk regardless of SED time among patients with T2DM.

Changes in physical activity,sedentary behavior,and self-reported cognitive function in cancer survivors before and during the COVID-19 pandemic:A cross-sectional study

Background Physical activity(PA)and reductions in sedentary behavior(SED)may mitigate cancer-related cognitive impairment.The purpose of this study was to examine(a)the associations between changes in PA,SED,and cognitive function in cancer survivors before and during the coronavirus disease 2019(COVID-19)pandemic;and(b)clinical subgroups that moderate this association.Methods A cross-sectional survey was administered online to adult cancer survivors globally between July and November of 2020.This was a secondary analysis of a cross-sectional survey examining changes in self-reported PA and quality of life in cancer survivors before and during the COVID-19 pandemic.Self-reported Questionnaires assessed moderate-to-vigorous PA(MVPA)using the modified Godin Leisure Time Exercise Questionnaire,cognitive function using the Functional Assessment of Cancer Therapy-Cognitive Function(FACT-Cog)scale,and SED using the Domain-specific Sitting Time questionnaire.Cancer survivors were classified into no change in behavior,desirable change(i.e.,increase MVPA to meet PA guidelines or decrease SED by≥60 min/day),and undesirable change(i.e.,decrease MVPA to<150 min/week or increase SED by≥60 min/day).Analysis of covariance examined differences in FACT-Cog scores across the activity change categories.Planned contrasts compared differences in FACT-Cog scores between cancer survivors with(a)no meaningful change vs.any change,and(b)a desirable change vs.an undesirable change.Results There were no significant differences in FACT-Cog scores across activity-change categories in the full sample of cancer survivors(n=371;age=48.6±15.3 years(mean±SD)).However,cancer survivors who were diagnosed≥5 years ago(t(160)=–2.15,p=0.03)or who received treatment≥5 years ago(t(102)=–2.23,p=0.03)and who had a desirable change in activity reported better perceived cognitive abilities than those who had an undesirable change.Conclusion PA promotion efforts should consider reducing SED in addition to maintaining MVPA in long-term cancer survivors to mitigate cancer-related cognitive impairment during the COVID-19 pandemic.

Ventilatory Disorders in Elite Athletes: Comparative Study between High-Level Athletes and Sedentary Subjects in a Sub-Saharan African Country

Background/Objective: Very intense and repeated exercise, particularly when performed over many years, could cause respiratory health problems. The combination of a sustained high ventilation and provocative training environments may impact the susceptibility of athletes to ventilatory disorders. Previous studies suggest that impaired ventilatory function in elite athletes can be detected in the absence of respiratory symptoms even after cessation of sports activity. The purpose of this study was to evaluate the ventilatory function of elite athletes compared to sedentary subjects. Material and Methods: This study included sedentary subjects and elite athletes, all male, aged 16 to 23 years. The athletes played regularly in the Senegalese league 1 championships (football and basketball) for at least two seasons with more than 10 hours of training per week during two years. For all participants, an interrogation was submitted and we conducted a clinic examination was performed following by a basic and post-bronchodilator spirometry. Results: The mean age of athletes (n = 66) and sedentary subjects (n = 61) was respectively 19.16 ± 2 years and 19.54 ± 2.12 years. The elite athletes presented significantly higher spirometry values (p Conclusion: This study found a high prevalence (72.73%) of ventilatory disorders (VD) in Senegalese elite athletes. Many previously undiagnosed elite athletes had significant ventilatory problems. To prevent the respiratory risk, athletes should be encouraged to avoid certain environmental factors and to adapt the period of their training.

Physical activity,sedentary behaviors,physical fitness,and their relation to health outcomes in youth with type 1 and type 2 diabetes:A review of the epidemiologic literature

Diabetes is a leading chronic disease of childhood and adolescence. In addition to the well-known auto-immune, insulin-dependent diabetes mellitus （type 1 diabetes （T 1D））, the past two decades have witnessed the emergence of type 2 diabetes （T2D） in children and adolescents, which previously was only seen in middle-aged or older adults. One of the key components of diabetes management is physical activity （PA）. The beneficial effects of increased PA and decreased sedentary behavior are extremely important in youth with diabetes because of the markedly increased long-term risk of cardiovascular disease in this population compared to persons without diabetes. This review aims to comprehensively summarize the epidemiologic, observational research published and listed in PubMed between 1970 and 2012 on PA and sedentary behaviors, as well as physical fitness in children and adolescents with T1D and T2D. Additionally, we describe briefly the state of knowledge on perceived barriers of PA in persons with diabetes, with a focus on hypoglycemia. Finally, we provide an overview of the epidemiological literature pertaining to health benefits of increased PA in youth with TID and T2D and briefly discuss the topic of exercise-related hypoglycemia, Copyright ~ 2012, Shanghai University of Sport. Production and hosting by Elsevier B.V. All rights reserved.

Physical Activity and Sedentary Behaviors among Chinese Children: Recent Trends and Correlates

Objective This study was aimed at examining the trends and correlates of physical activity(PA)and sedentary behaviors among Chinese children.Methods A total of 4,341 subjects(6,936 observations)aged 6–17 years who participated in the China Health and Nutrition Survey(2004–2015)were included.Of the subjects,41%participated in the survey twice or more.Random-effects ordinal regression models and repeated-measures mixed-effects models were used to examine the PA trends.Quantile regression models were applied to examine the factors influencing PA and sedentary behaviors.Results From 2004 to 2015,the prevalence of physical inactivity among Chinese children aged 6–17 years increased by 5.5%[odds ratio(OR),1.51;95%confidence interval(CI),1.19–1.90;P<0.001].The PA volume declined by 5.8 metabolic equivalent of task-hr/week(P<0.001),and the time spent in sedentary behaviors increased by 1.8 hr/week(P<0.001).Age,ethnicity,and region showed significant effects on the PA volume across the quartiles(P<0.001).Across the quartiles,sedentary time was significantly higher in the children residing in urban areas(P<0.001)or areas with high urbanization levels(P≤0.005)than in their counterparts.Conclusions A declining PA trend among Chinese children aged 6–17 years was observed from 2004 to2015,and certain subgroups and geographical areas are at higher risk of physical inactivity.

Adverse associations of sedentary behavior with cancer incidence and all-cause mortality:A prospective cohort study

Background:Inconsistent results have been reported in developed countries for relationships between sedentary behavior and cancer incidence and mortality,and evidence from the Chinese population is scarce.This study aimed to investigate such relationships in large Chinese population-based prospective cohorts and to explore the joint effect and interaction of sedentary behavior and moderate-to-vigorous physical activity(MVPA)on these relationships.Methods:We included 95,319 Chinese adults without cancer from 3 large cohorts and assessed their sedentary behavior and physical activity with a unified questionnaire.Cancer incidence and mortality were confirmed by interviewing participants or their proxies and checking hospital records and death certificates.Hazard ratios(HRs)and 95%confidence intervals(95%CIs)for cancer and mortality were estimated using Cox proportional hazards regression models.Results:During 559,002 person-years of follow-up,2388 cancer events,1571 cancer deaths,and 4562 all-cause deaths were recorded.Sedentary behavior was associated with increased risk of developing cancer and deaths in a doseresponse manner.The multivariable-adjusted HRs(95%CIs)were the following:HR=1.16,95%CI:1.01-1.33;HR=1.24,95%CI:1.04-1.48;and HR=1.15,95%CI:1.04-1.28 for cancer incidence,cancer mortality,and all-cause mortality,respectively,for those having≥10 h/day of sedentary time compared with those having<6 h/day of sedentary time.Sedentary populations(≥10 h/day)developed cancer or died 4.09 years and 2.79 years earlier,respectively,at the index age of 50 years.Failure to achieve the recommended level of MVPA may further aggravate the adverse associations,with the highest cancer and mortality risks being observed among participants with both≥10 h/day of sedentary time and<150 min/week of MVPA.Limitations of this study include the fact that physical activity information was obtained via questionnaire instead of objective measurement and that there were insufficient incident cases for the analysis of associations between sedentary behavior and site-specific cancers.Conclusion:Sedentary behavior was associated with an increased risk of cancer and all-cause mortality among Chinese adults,especially for those with≥10 h/day of sedentary time.It is necessary to reduce sedentary time,in addition to increasing MVPA levels,for the prevention of cancer and premature death.

医学新名词:体力活动缺乏综合症(Sedentary Death Syndrome)

大量的研究已证实,体力活动缺乏和许多慢性疾病的发生以及由此而引起的死亡密切相关.

Cardiometabolic risk through an integrative classification combining physical activity and sedentary behavior in European adolescents:HELENA study

Purpose: This study aims to compare adolescents' cardiometabolic risk score through an integrative classification of physical activity(PA),which involves the combination of moderate-to-vigorous physical activity(MVPA) and sedentary behavior(SB).Methods: A cross-sectional study derived from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study database(2006-2008) was conducted in adolescents(n = 548; boys, 47.3%; 14.7 ± 1.2 years) from 10 European cities. MVPA and SB were objectively measured using accelerometry. Adolescents were divided into 4 categories according to MVPA(meeting or not meeting the international recommendations) and the median of SB time(above or below sex-and age-specific median) as follows: High-SB & Inactive, Low-SB & Inactive,High-SB & Active, and Low-SB & Active. A clustered cardiometabolic risk score was computed using the homeostatic model assessment, systolic blood pressure, triglycerides, total cholesterol/high-density lipoprotein cholesterol, sum 4 skinfolds, and cardiorespiratory fitness(CRF).Analyses of covariance were performed to discern differences on cardiometabolic risk scores among PA categories and each health component.Results: The cardiometabolic risk score was lower in adolescents meeting the MVPA recommendation and with less time spent in SB in comparison to the high-SB & Inactive group(p < 0.05). However, no difference in cardiometabolic risk score was established between High-SB or Low-SB groups in inactive adolescents. It is important to note that CRF was the only variable that showed a significant modification(higher)when children were compared from the category of physically inactive with "active" but not from high-to low-SB.Conclusion: Being physically active is the most significant and protective outcome in adolescents to reduce cardiometabolic risk. Lower SB does not exhibit a significant and extra beneficial difference.

Social correlates of sedentary behavior in young people:The UP&DOWN study

Purpose:The aim of the present study was to analyze the associations of youths' sedentary behavior(SB) with parents' and siblings' SB and physical activity(PA),as well as the associations of youths' coparticipation with parents,siblings,and friends in PA and SB with youths' SB.Methods:The sample consisted of 1543 youths(12.02±2.51 years;788 boys) enrolled in the baseline cohort of the UP&DOWN study.SB was assessed by accelerometry and questionnaire.Participants reported the time spent by their parents and siblings watching television,playing videogames,surfing the Internet,sitting/resting,and doing PA.Further,participants reported coparticipation with parents,siblings,and friends in these activities.Linear mixed models,including school and city as random effects,were performed.Results:Parents' television time was positively associated with youths' screen-based SB.Coparticipation with friends in playing videogames(in boys) and in surfing the Internet(in girls) showed a positive association with screen-based SB and a negative association with educational-based SB.Moreover,coparticipation with siblings and friends in PA was inversely associated with accelerometer-based SB in boys and girls.Conclusion:Our results emphasize the important role of social modeling in the development of sedentary lifestyles in youths.Interventions aimed at reducing health risk behaviors in youths could be more effective if they are oriented from a social perspective that involves their families and networks of their closest friends.

Associations of Sedentary Time and Physical Activity with Metabolic Syndrome among Chinese Adults:Results from the China Health and Nutrition Survey

Objective This study aimed to determine the independent and joint associations of sedentary time(ST)and physical activity(PA) with metabolic syndrome(MetS) and its components among Chinese adults.Methods The study analyzed data from 4,865 adults aged ≥ 18 years who participated in the 2009 and2015 China Health and Nutrition Surveys(CHNS). Four types of leisure ST and three types of PA selfreported at baseline were collected. Multivariable logistic regressions were used to determine the independent and joint associations of ST and PA with the odds of MetS or its components.Results For independent effects, higher levels of television time and total leisure ST was associated with higher MetS risk [odds ratio(OR) 1.3, 95% confidence interval(CI) 1.1–1.6, P < 0.001;OR 1.4, 95% CI1.2–1.8, P < 0.001, respectively]. The MetS risk in the computer time > 7 hours/week(h/w) group was higher than that in the < 7 h/w group in(OR 1.5, 95% CI 1.2–1.9). Higher levels of moderate-to-vigorousintensity physical activity(MVPA) and total PA were associated with a lower MetS risk(OR 0.7, 95% CI0.6–0.9, P < 0.001;OR 0.8, 95% CI 0.7–0.9, P < 0.001, respectively). For the joint effects, compared with those reporting the lowest level of total leisure ST(< 14 h/w) and the most active tertile of MVPA(≥ 61.0 MET-h/w), participants reporting the most total leisure ST(≥ 35 h/w) and the lowest level of MVPA(0 MET-h/w) had the highest odds of MetS(OR 2.0;95% CI 1.4–2.7). Except for people reporting ST(14–21 h/w) within the most active tertile of MVPA, the associations in all other groups were significant.With the increase of TV time and decreased MVPA, the odds of MetS almost showed a curve acceleration.Conclusions MVPA and total PA have independent preventive effects, and sedentary behavior(mainly watching TV) has an unsafe effect on MetS and its components. Strengthening the participation of MVPA and combining the LPA to replace the TV-based ST to increase the total PA may be necessary to reduce the prevalence of MetS in Chinese adults.

A mixed-studies systematic review and meta-analysis of school-based interventions to promote physical activity and/or reduce sedentary time in children

Purpose:The aim of this mixed-studies systematic review was to ascertain the effectiveness of school-based interventions in increasing physical activity(PA) and/or reducing sedentary time(ST) in children aged 5-11 years,as well as to explore their effectiveness in relation to categories of the theory of expanded,extended,and enhanced opportunity(TEO).Methods:Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) guidelines,5 databases were searched using predefined search terms.Following title and abstract screening of 1115 records,the removal of duplicates(n=584) and articles that did not meet the inclusion criteria agreed to a priori(n=419) resulted in 112 records that were full-text screened.Two independent reviewers subsequently used the mixed-methods appraisal tool to assess the methodological quality of 57 full-text studies that met the inclusion criteria after full-text screening.The interventions were summarised using the TIDierR checklist and TEO.The strength of evidence was determined using a 5-level rating system utilising a published decision tree.Results:Overall evidence ratings for interventions implemented within school settings were:no evidence of effects on moderate-to-vigorous physical activity(MVPA) and inconclusive evidence of effects on sedentary time.In relation to the TEO,expansion of PA appeared to be the most promising intervention type for MVPA,with moderate evidence of effect,whereas extension and enhancement of PA opportunity demonstrated no evidence of effect.A critical issue of possible compensatory behavior was identified by analysis of intervention effect in relation to PA measurement duration;when studies measured changes in PA during the actual intervention,there was moderate evidence of effect,whereas those that measured changes in PA during the school day presented inconclusive evidence of effect,and those that measured changes in PA over a whole day yielded no evidence of effect.Two meta-analyses of those studies using a whole-day accelerometer measure for MVPA or ST showed a significant but moderate effect for MVPA(effect size=0.51;95% confidence interval(CI):0.02-0.99) and a large but nonsignificant effect for ST(effect size=1.15;95%CI:-1.03 to 3.33);both meta-analyses demonstrated low precision,considerable inconsistency,and high heterogeneity.Conclusion:The findings have important implications for future intervention research in terms of intervention design,implementation,and evaluation.

Physical exercise,Sedentary Behaviour,Sleep and Depression Symptoms in Chinese Young Adults During the COVID-19 Pandemic:A Compositional Isotemporal Analysis

Numerous studies links movement activity(e.g.,physical activity,sedentary behavior[SB],and sleep)with mental health or illness indicators during the COVID-19 pandemic;however,research has typically examined time-use behaviors independently,rather than considering daily activity as a 24-hour time-use composition.This cross-sec-tional study aimed to use compositional isotemporal analysis to estimate the association between reallocation of time-use behaviors and depression symptoms in young adults in China.Participants(n=1475;68.0%of female;20.7[1.60]years)reported their time spent in moderate to vigorous physical activity(MVPA),light physical activ-ity(LPA),SB,and sleep.Replacing SB with sleep,LPA,and MVPA at 5,10,or 15 min was significantly associated with lower estimated depression symptoms scores.For example,adding MVPA from SB at 15 min was associated with lower depression symptoms scores(estimated difference:-0.13[-0.17,-0.09]).The associations between reallocation of time use behaviors with depression symptoms scores were slightly differentiated.Our results emphasize the importance of increased MVPA and decreased SB as well as their mutual replacements for lowering the risks of depression symptoms in young adults during the COVID-19 pandemic.Our results can inform policy to develop effective plans and strategies for mental health promotion.

Activity-related typologies and longitudinal change in physical activity and sedentary time in children and adolescents:The UP&DOWN Study

Background:Children and adolescents can be distinguished by different typologies(clusters) of physical activity and sedentary behavior.How physical activity and sedentary behaviors change over time within different typologies is not known.This study examined longitudinal changes in physical activity and sedentary time among children and adolescents with different baseline typologies of activity-related behavior.Methods:In this longitudinal study(3 annual time points) of children(n=600,age=9.2±0.4 years(mean±SD),50.3% girls) and adolescents(n=1037,age=13.6±1.7 years,48.4% girls),participants were recruited in Spain in 2011-2012.Latent class analyses identified typologies based on self-reported screen,educational,social and relaxing sedentary behaviors,active travel,muscle strengthening activity,and sport at baseline.Within each typology,linear mixed growth models explored longitudinal changes in accelerometer-derived moderate-to-vigorous physical activity and sedentary time,as well as time by class interactions.Results:Three typologies were identified among children( "social screenies",12.8%;"exercisers",61.5%;and "non-sporty active commuters",25.7%) and among adolescents "active screenies",43.5%;"active academics",35.0%;and "non-sporty active commuters",21.5%) at baseline.Sedentary time increased within each typology among children and adolescents,with no significant differences between typologies.No changes in physical activity were found in any typology among children.In adolescents,physical activity declined within all typologies,with "non-sporty active commuters" declining significantly more than "active screenies" over 3 years.Conclusion:These results support the need for interveation to promote physical activity and prevent increases in sedentary time during childhood and adolescence.Adolescents characterized as "non-sporty active commuters" may require specific interventions to maintain their physical activity over time.

Sensor-based physical activity, sedentary time, and reported cell phone screen time: A hierarchy of correlates in youth

Background:Evidence on correlates relies on subjective metrics and fails to include correlates across all levels of the ecologic model.We determined which correlates best predict sensor-based physical activity(PA),sedentary time(ST),and self-reported cell phone screen time(CST)in a large sample of youth,while considering a multiplicity of correlates.Methods:Using sensor-based accelerometry,we assessed the PA and ST of 2179 youths.A χ^2 automatic interaction detection algorithm was used to hierarchize the correlates associated with too much ST(>50th percentile),insufficient moderate-to-vigorous PA(MVPA)(<60 min/day),and prolonged CST(≥2 h/day).Results:Among youth 10-14 years old,the correlates for being inactive consisted of being a girl,not having sport facilities in the neighborhood,and not perceiving the neighborhood as a safe place,whereas in the youth 15-18 years old,the correlate for being inactive was not performing sports(9.7%chance of being active).The correlates for predicting high ST in the younger group was not performing sports(55.8%chance for high ST),and in the older group,the correlates were not owning a pet,perceiving the neighborhood as safe,and having inactive parents(63.7%chance for high ST).In the younger group,the greatest chances of having high CST were among those who were in the last elementary school years,who were girls,and who did not have friends in the neighborhood(73.1%chance for high CST),whereas in the older group,the greatest chance for having high CST was among those who were girls and had a TV in the bedroom(74.3%chance for high CST).Conclusion:To counteract ST and boost MVPA among youths,a specific focus on girls,the promotion of sport participation and facilities,neighborhood safety,and involvement of family must be prioritized.

Associations of physical activity, sedentary time, and physical fitness with mental health during pregnancy: The GESTAFIT project

Purpose:This study was aimed to analyze the associations of objectively measured physical activity(PA),sedentary time,and physical fitness with mental health in the early second trimester(16§2 gestational weeks)of pregnancy.Methods:From 229 women initially contacted,124 pregnant women participated in the present cross-sectional study.Data were collected between November 2015 and March 2017.The participants wore Actigraph GT3X+Triaxial accelerometers for 9 consecutive days to objectively measure their PA levels and sedentary time.A performance-based test battery was used to measure physical fitness.Self-report questionnaires assessed psychological ill-being(i.e.,negative affect,anxiety,and depression),and psychological well-being(i.e.,emotional intelligence,resilience,and positive affect).Linear regression analyses were adjusted for age,educational level,accelerometer wear time,miscarriages,and low back pain.Results:Moderate-to-vigorous PA was negatively associated with depression(b=0.222,adjusted R2=0.050,p=0.041).Higher levels of sedentary time were negatively associated with positive affect(b=0.260,adjusted R2=0.085,p=0.017).Greater upper-body flexibility was positively associated with better emotional regulation(b=0.195,adjusted R2=0.030,p=0.047).The remaining associations were not significant(all p>0.05).Conclusion:An active lifestyle characterized by higher levels of moderate-to-vigorous PA and lower levels of sedentary time during pregnancy might modestly improve the mental health of pregnant women.Although previous research has focused on the benefits of cardiorespiratory exercise,the present study shows that only upper-body flexibility is related to emotional regulation in early pregnant women.If the present findings are corroborated in further experimental research,physical exercise programs should focus on enhancing flexibility to promote improvements in emotional regulation during early second-trimester of pregnancy.

The Relationship Between Plant Community Characteristics and Soil Organic Matter Content of Sedentary Grazing Pastures in a Typical Steppe

In order to discuss the relationship between the characteristics of plant communities and the content of topsoil organic matter under the condition of two-season sedentary grazing, authors of this paper selected a Stipa krylovii steppe for research and studied the plant community characteristics and the topsoil organic matter content. The results showed that in the sedentary grazing area, the perennial plant species decreased, the annual plant species increased, and the topsoil organic matter content decreased. There were a negative correlation between plant biomass and topsoil organic matter content, and a positive correlation between total coverage and topsoil organic matter content. The change of plant community characteristics in the sedentary grazing area was related to the implementation of the system of transferring the pasture use rights to the herdsmen and controlled grazing.