Associations Between Type and Timing of Physical Activity and Sedentary Behavior With Mental Health in Adolescents and Young Adults.

BACKGROUND: This cross-sectional study analyzed the association of leisure-time physical activity (PA) and sedentary behavior (SB), nonleisure PA and SB, and total PA and SB in different time segments of the day with mental health among Dutch adolescents and young adults. METHODS: A total of 881 participants aged 16-25 years completed an online survey. Mental health was assessed using the Mental Health Inventory-5, and participants also reported sex, age, and income. They filled out a questionnaire of types of PA and SB for each hour of the day. Activities were categorized into nonleisure and leisure, during the morning, afternoon, evening, and for the whole day. RESULTS: Participants (52.8% female, on average 20.8 y) generally engaged in more leisure-time PA and SB during weekends compared with weekdays, and more nonleisure activities on weekdays. Associations varied between time segments and days of the week. Positive associations of leisure-time and total PA during the whole day and evenings with mental health were observed on weekdays. Total, leisure-time, and nonleisure-time SB were associated with worse mental health. Nonleisure PA was not associated with mental health. CONCLUSIONS: Leisure-time PA was found to have a favorable association with mental health, particularly in the evenings of weekdays and afternoons of weekend days. On the other hand, leisure SB was associated with poorer mental health in most of the time segments analyzed, and nonleisure SB in the evenings was also related to worse mental health. The type and timing of PA and SB behaviors play an important role in the relationship with mental health.

The role of insufficient sleep and circadian misalignment in obesity.

Traditional risk factors for obesity and the metabolic syndrome, such as excess energy intake and lack of physical activity, cannot fully explain the high prevalence of these conditions. Insufficient sleep and circadian misalignment predispose individuals to poor metabolic health and promote weight gain and have received increased research attention in the past 10 years. Insufficient sleep is defined as sleeping less than recommended for health benefits, whereas circadian misalignment is defined as wakefulness and food intake occurring when the internal circadian system is promoting sleep. This Review discusses the impact of insufficient sleep and circadian misalignment in humans on appetite hormones (focusing on ghrelin, leptin and peptide-YY), energy expenditure, food intake and choice, and risk of obesity. Some potential strategies to reduce the adverse effects of sleep disruption on metabolic health are provided and future research priorities are highlighted. Millions of individuals worldwide do not obtain sufficient sleep for healthy metabolic functions. Furthermore, modern working patterns, lifestyles and technologies are often not conducive to adequate sleep at times when the internal physiological clock is promoting it (for example, late-night screen time, shift work and nocturnal social activities). Efforts are needed to highlight the importance of optimal sleep and circadian health in the maintenance of metabolic health and body weight regulation.

Association of daily and time-segmented physical activity and sedentary behaviour with mental health of school children and adolescents from rural Northeastern Ontario, Canada.

Physical activity (PA) and sedentary behaviour (SED) have been linked to the mental health of children and adolescents, yet the timing of behaviours may play a role in this relationship and clarifying this could inform interventions. We explored cross-sectional associations of PA and SED in varying time segments throughout the school day with the mental health of school-aged children and adolescents from rural Northeastern Ontario, Canada. A total of 161 students (56% female, M = 10.3 years old) wore accelerometers for 8 days (7 nights) and completed a self-report survey (parent reported for children younger than 11). Mental health was measured using the Strengths and Difficulties Questionnaire. Accelerometer-measured SED, light PA (LPA), and moderate and vigorous PA (MVPA) were estimated in the time-segments before school (06:00-08:44), school time (08:45-15:04), after school (15:05-16:59), and evenings (17:00-21:59). Associations were tested with multilevel linear regressions while adjusting for confounding factors. Students spent 72.6 min in MVPA, 209.0 min in LPA, and 621.0 min in SED per day. Daily SED was associated with less conduct problems (ß = -0.27, p < 0.05). Evening LPA was inversely associated with hyperactivity (ß = -1.45, p < 0.05), while SED was associated with hyperactivity and with peer problems before school (ß = 1.70 and ß = 1.01, respectively, p < 0.05), and during school (ß = -0.83 and ß = -0.57, respectively, p < 0.05). No associations were observed for MVPA, emotional symptoms, or prosocial behaviour. In conclusion, displacing SED with LPA in some specific periods of the day may benefit the mental health of students; taking this into account could strengthen interventions.

School-related sedentary behaviours and indicators of health and well-being among children and youth: a systematic review.

BACKGROUND: The purpose of this systematic review was to examine the associations between school-related sedentary behaviours and indicators of health and well-being in children and youth (~ 5-18 years) attending school. METHODS: This review was conducted to inform the development of School-Related Sedentary Behaviour Recommendations. Peer-reviewed, published, or in-press articles in English were included. Reviews, meta-analyses, and case studies were excluded; all other study designs were eligible. Further, articles had to meet the a priori study criteria for population, intervention, comparator (PROSPERO ID: CRD42021227600). Embase, MEDLINE® ALL, and PsycINFO were searched. Risk of bias was assessed for individual experimental studies using the Cochrane risk of bias assessment tool, and in observational studies based on the GRADE framework and in line with previous systematic reviews examining sedentary behaviours in children. Overall quality of evidence was assessed using the GRADE framework for each outcome category and study design. Results were synthesized narratively, grouped by study design and outcome category. Further, several high-level summaries were conducted to help interpret results. RESULTS: Evidence was synthesized from 116 reports, including 1,385,038 participants and 1173 extracted associations. More school-related sedentary behaviour was favourably associated with nearly one-third of extracted associations for cognitive (33%) and social-emotional (32%) indicators (e.g., less anxiety), but unfavourably associated with other movement behaviours (e.g., less physical activity) (35%). Active lessons were favourable (72%), compared to more school-related sedentary behaviours, when examining associations for all health and well-being indicators. More homework was favourable across all health and well-being indicators in 4% of extracted associations for primary school children, and 25% of extracted associations for secondary school children. However, ≥2 h/day of homework appeared to be unfavourable for health and well-being. Limitations for synthesized studies included generally low quality of evidence and a lack of studies in South American, African, or low-middle income countries. CONCLUSIONS: Findings can help inform policy makers, schools, and teachers, regarding the amount of homework assigned and the introduction of active lessons into the classroom to enhance health and well-being of children. More research is needed examining school-related sedentary behaviours and indicators of health and well-being in low- and middle-income countries.

International school-related sedentary behaviour recommendations for children and youth.

BACKGROUND: Existing sedentary behaviour guidelines for children and youth target overall sedentary behaviour and recreational screen time, without any specific recommendations regarding school-related sedentary behaviours (i.e., sedentary behaviours performed during the school day, or within the influence of school). The purpose of this paper is to describe the development of international evidence-based recommendations for school-related sedentary behaviours for children and youth, led by the Sedentary Behaviour Research Network (SBRN). METHODS: A panel of international experts was convened by SBRN in November 2020 to guide the development of these recommendations for children and youth aged ~ 5-18 years. The recommendations were informed by 1) age-relevant existing sedentary behaviour guidelines, 2) published research on the relationship between overall sedentary behaviour and health, 3) a de novo systematic review on the relationship between school-related sedentary behaviours and health and/or academic outcomes, and 4) a de novo environmental scan of the grey literature to identify existing recommendations for school-related sedentary behaviours. Draft recommendations were presented to the Expert Panel in June 2021. Following thorough discussion and modifications, updated recommendations were distributed for stakeholder feedback from July 9-26. Feedback was received from 148 stakeholders across 23 countries, leading to additional updates to the recommendations. Following further rounds of discussion and updates with the Expert Panel in August and September 2021, consensus was achieved on the final recommendations. RESULTS: A healthy day includes breaking up extended periods of sedentary behaviour and incorporating different types of movement into homework whenever possible, while limiting sedentary homework. School-related screen time should be meaningful, mentally or physically active, and serve a specific pedagogical purpose that enhances learning. Replacing sedentary learning activities with movement-based learning activities, and replacing screen-based learning activities with non-screen-based learning activities, can further support students' health and wellbeing. DISCUSSION: This paper presents the first evidence-based recommendations for school-related sedentary behaviours for children and youth. These recommendations will support the work of parents, caregivers, educators, school system administrators, policy makers, researchers and healthcare providers interested in promoting student health and academic success.

A higher energy-adjusted Dietary Inflammatory Index is positively associated with total and visceral body fat in young male adults.

BACKGROUND: The energy-adjusted Dietary Inflammatory Index (E-DII™) has been associated with a high body mass index and markers of chronic diseases. Also, pro-inflammatory diets with a high E-DII have been positively associated with metabolic disturbances such as glucose intolerance and type II diabetes mellitus. However, it is unclear whether E-DII scores are positively associated with body fat percentage and visceral fat per se. This cross-sectional study aimed to evaluate whether the E-DII is associated with body fat content and metabolic health indicators in lean and obese young men. METHODS: The present study was conducted on 59 participants, without comorbidities, not using tobacco, medication and nutritional supplements. Dietary data were obtained by 3-day food records to calculate E-DII scores based on 28 food parameters. Body composition was assessed by dual X-ray absorptiometry (DXA). Blood samples were taken to measure fasting glucose, insulin, triacylglycerols, total cholesterol, and low- and high-density lipoprotein cholesterol. An oral glucose tolerance test also was performed. Associations were determined by mixed-effects linear regression. RESULTS: E-DII scores ranged from -3.48 to +3.10. Energy intake was similar across E-DII tertiles. After adjusting for covariates, the highest E-DII tertile was associated with increased body fat, visceral adipose tissue and waist circumference. There was no association between E-DII scores and glycaemic parameters. CONCLUSIONS: In young participants, a dietary pattern with a higher E-DII (i.e., pro-inflammatory) score was associated with high body fat and markers of central adiposity assessed by DXA, regardless of body mass.

School schedule affects sleep, but not physical activity, screen time and diet behaviors.

BACKGROUND: Behavioral changes during adolescence are affected by biological and social aspects. However, environment aspects, which are beyond adolescents' control, also contribute to behavior adoption, and school may have a significant impact in these behaviors. This cross-sectional study aims to investigate how lifestyle behaviors are associated with the school shift attended by high school students. METHODS: The sample comprised 635 high school students (51.2% girls, 16.33 ± 1.0 years old) from Southern Brazil. Physical activities of different intensities (light and moderate-to-vigorous), sedentary behaviors, and sleep (duration, efficiency, and timing) were measured using accelerometers. Engagement in sport and non-sport activities, screen time indicators, and diet were self-reported. Linear models were fitted to compare each lifestyle behavior between the two school shifts. RESULTS: Students attending the afternoon shift slept (ß = 01:29 95%CI 01:13; 01:46) and woke up later (ß = 01.41 95%CI 01:27; 01:54), and had a longer sleep duration (ß = 00:12 95%CI 0:02; 00:21) than those attending the morning shift. However, the sleep efficiency of those in the afternoon shift was lower than their peers in the morning shift (ß = -1.89 95%CI -3.01; -0.77). CONCLUSIONS: School schedule was associated with sleep behaviors of adolescents, but not with other lifestyle behaviors.

Psychosocial correlates of objectively measured in-school and out-of-school physical activity among Brazilian adolescents.

Physical activity is influenced by an interplay of time and setting, thus, the role of psychosocial factors on behavior is expected to vary across the day. This cross-sectional study identified the psychosocial correlates of time spent in physical activity during in-school (i.e., 08:00-11:59) and out-of-school (i.e., 12:00-22:00) time segments. The sample consisted of adolescents (7th to 9th grade) of two public schools in Florianópolis, Brazil. Accelerometer measured light-intensity (LPA) and moderate-to-vigorous-intensity physical activity (MVPA) were estimated. Psychosocial correlates of physical activity (i.e., outcome expectations, attitude, self-efficacy, support from parents, and support from peers) were self-reported. Linear mixed models were applied and interaction effects of gender and age were also analyzed. From a total of 194 participants, 138 and 112 provided in-school and out-of-school valid data, respectively. Outcome expectations were associated with out-of-school MVPA (ß = 0.18; p = .006). Age interaction effects were observed for the associations between outcome expectations and out-of-school LPA (ß = 0.21; p = .009) and between self-efficacy and out-of-school MVPA (ß = 0.19; p = .009). In conclusion, psychosocial correlates were positively associated with out-of-school physical activity and the effects varied according to age. No psychosocial correlates were identified for LPA and MVPA performed during schooltime.

Efforts on Changing Lifestyle Behaviors May Not Be Enough to Improve Health-Related Quality of Life Among Adolescents: A Cluster-Randomized Controlled Trial.

Schools have been the main context for physical activity (PA) and sedentary behavior (SB) interventions among adolescents, but there is inconsistent evidence on whether they also improve dimensions of the health-related quality of life (HRQoL). The aim of this study was to evaluate the effects of a school-based active lifestyle intervention on dimensions of HRQoL. A secondary aim was to verify whether sex, age, and HRQoL at baseline were moderators of the intervention effect. A cluster-randomized controlled trial was conducted at three control and three intervention schools in Florianopolis, Brazil. All students from 7th to 9th grade were invited to participate. A school year intervention, designed primarily to increase PA and reduce SB, included strategies focused on (i) teacher training on PA, SB, and nutrition, and availability of teaching materials related to these contents; (ii) environmental improvements (i.e., creation and revitalization of spaces for the practice of PA in school); and (iii) education strategies, with the availability of folders and posters regarding PA, SB, and nutrition. Participants and the research staffs were not blinded to group assignment, but a standardized evaluation protocol was applied at baseline and after the intervention (March and November 2017) using the KIDSCREEN-27 to assess HRQoL across five dimensions. Mixed linear models were performed to evaluate the effect of the Movimente intervention on the five HRQoL dimensions. Of the 921 students who answered the questionnaire at baseline, 300 and 434 completed the study in control and intervention groups, respectively (dropouts: 20%). The results revealed no significant effects of the intervention on any HRQoL dimensions. A reduction of the school environment dimension was observed in both the control (-2.44; 95% CI: -3.41 to -1.48) and intervention groups (-2.09; 95% CI: -2.89 to -1.30). Sensitivity analyses showed that students in the highest baseline tertiles of HRQoL in any dimension had a reduction in their respective scores from pre- to post-intervention in both school groups. In conclusion, our results demonstrated no intervention effect on HRQoL dimensions and those students with the highest levels of HRQoL at baseline on all dimensions reduced from pre to post-intervention. CLINICAL TRIAL REGISTRATION: The trial is registered at the Clinical Trial Registry (Trial ID: NCT02944318; date of registration: October 18, 2016).

Association between physical activity, screen time activities, diet patterns and daytime sleepiness in a sample of Brazilian adolescents.

OBJECTIVE: To examine the association between physical activity, screen time, eating habits and daytime sleepiness among Brazilian adolescents. METHODS: Adolescents from three high schools (n = 876, 49.8% female, 16.4 ± 1.2 years) participated in this cross-sectional survey. Variables related to lifestyle behaviors (ie, physical activity, screen time, eating habits, sleep duration) were collected through an online questionnaire. Daytime sleepiness was assessed using the Pediatric Daytime Sleepiness Scale (PDSS). Excessive daytime sleepiness was defined as a PDSS score ≥20. RESULTS: The average PDSS score was 18.9 (SD ± 4.8) points and 46.8% of adolescents were classified as having excessive daytime sleepiness. Physical activity was inversely associated with PDSS score (ß = -0.29, 95% CI -0.47; -0.11). Consuming processed foods frequently (ß = 1.16, 95% CI 0.85; 1.47) and using social media (ß = 0.22, 95% CI 0.14; 0.30) were positively associated with PDSS score. Similar findings were observed for the odds of excessive daytime sleepiness. Physical activity was inversely associated (OR = 0.91, 95% CI 0.84; 0.99), while frequent consumption of processed foods (OR = 1.55, 95% CI 1.33; 1.82) and using social media (OR = 1.13, 95% CI 1.02; 1.24) were positively associated with excessive daytime sleepiness. CONCLUSIONS: Lower physical activity level, a higher consumption processed foods, and higher social media use were associated with daytime sleepiness in this sample of Brazilian adolescents.

Prevalence and sociodemographic factors associated with meeting the 24-hour movement guidelines in a sample of Brazilian adolescents.

BACKGROUND: The present cross-sectional study aimed to determine the proportion of adolescents meeting the 24-hour movement guidelines, and investigate sociodemographic factors associated with meeting them. METHODS: Self-reported (average daily volume of MVPA, sleep duration, and time watching videos and playing videogames) and accelerometer-measured (MVPA and sleep duration) 24-hour movement behaviors were classified according to recommendations, and sex, age, socioeconomic status (SES), family structure, parental education, and number of people in the household were tested as correlates of meeting recommendations using multilevel logistic regressions. RESULTS: The proportion of adolescents (n = 867, mean age: 16.4 years, 50.3% girls) meeting the MVPA, ST, and sleep duration guidelines was of 25%, 28%, and 41%, respectively, for self-reported data. From accelerometer data (n = 688), 7.1% met MVPA and 31.7% met sleep duration recommendations. Adherence to all three recommendations was 3% with self-report and 0.2% with accelerometer data. Boys were more likely to meet MVPA, but not ST and sleep-duration recommendations. A positive relationship was observed between age and meeting the ST recommendation. CONCLUSIONS: Adherence to the sleep duration recommendation was higher than to the screen-time and MVPA recommendations and few in this sample of Brazilian adolescents achieved the 24-hour guidelines. Efforts are needed to improve 24-hour movement behaviors.

Patterns of Objectively and Self-Reported Sedentary Behavior in Children and Adolescents Living With Human Immunodeficiency Virus: The PositHIVe Health Study.

PURPOSE: Sedentary behavior (SB) has been shown to be associated with unhealthy outcomes in children, and it is not clear whether children living with human immunodeficiency virus (HIV) engage in different patterns of SB compared with healthy children. This cross-sectional study aimed to compare patterns of SB between children living with HIV and a healthy control group. METHODS: A group of children with HIV and a paired control group wore accelerometers for 1 week and answered a questionnaire with items related to television viewing habits and computer usage. Accelerometer-derived and self-reported SB were compared between children living with HIV and controls and between treatment-based and viral load subgroups. RESULTS: A total of 130 children (of which 53% are girls with a mean age of 12.1 y) participated in the study with 65 in each group. Children in the control group exhibited significantly more objectively measured SB daily when compared with the HIV group (515 vs 490 min/d, respectively), but no differences were found between the treatment-based and viral load subgroups. Children with HIV watched more television on weekdays, compared with the control group (P < .05). No other differences were found in comparisons of self-reported SB between the control and HIV and the treatment-based or viral load subgroups. CONCLUSION: Children living with HIV spend less time being sedentary than those in the healthy control group. Future studies are important for clarifying the causes and consequences of these differences.

Clustering of screen time behaviours in adolescents and its association with waist circumference and cardiorespiratory fitness.

OBJECTIVES: To identify the association of clusters of screen time (ST) behaviours with waist circumference (WC) and cardiorespiratory fitness (CRF) among adolescents. DESIGN: Cross-sectional study of 574 adolescents (53% girls, 13 years), conducted in 2017. METHODS: Waist circumference was measured, a shuttle run was performed to assess CRF, and a questionnaire was applied. Sex, age, socioeconomic status was reported, and daily duration of ST indicators for television viewing, computer use, videogame playing, and cellphone use, in weekdays and weekend days. Latent class analysis was performed to identify typologies of ST behaviours. Mixed-effects linear regressions were used to test the association of ST clusters with WC and CRF. RESULTS: Participants' WC was 66.9±8cm and CRF was 39.5±4mlO2/kg/min. Four clusters were identified: "Low ST" (25%); "High ST" (20%); "Gamers" (17%); and "High cellphone" (39%). No significant associations were found between ST clusters and WC. Maximum oxygen uptake was higher in those in the "Low ST" cluster compared to the other clusters. No significant interactions for sex were observed. CONCLUSIONS: Typologies of ST behaviours do not seem to be related to WC; however, those in the Low ST cluster had higher CRF compared to their peers in the other clusters, suggesting that total ST may be more important for CRF than specific indicators.

Sociodemographic, biological, and psychosocial correlates of light- and moderate-to-vigorous-intensity physical activity during school time, recesses, and physical education classes.

BACKGROUND: Identifying factors associated with physical activity (PA) is useful in planning interventions and policies. The aim of this study was to identify sociodemographic, biological, and psychosocial factors associated with PA performed in school settings. METHODS: Data collected for the present study included gender, age, socioeconomic status, body fat percentage, aerobic fitness, self-efficacy, attitudes, peer and parental support, and perception of school environment. Dependent variables were light-intensity PA (LPA) and moderate-to-vigorous-intensity PA (MVPA) performed during school time, recesses, and physical education (PE) classes. Multiple regression analyses were performed. RESULTS: Participating adolescents (n = 567, 53% female, 12.9 ± 5.3 years) spent 5% of school time in MVPA and 27% in LPA, 15% of recesses in MVPA and 44% in LPA, and 16% of PE classes in MVPA and 41% in LPA. Boys engaged in more MVPA in all categories. Age was inversely related with MVPA and LPA in all periods, whereas body fat percentage was inversely related with MVPA in school time and PE classes. Attitude was inversely related with MVPA in all periods and with LPA in recesses. Considering PA to be good and enjoyable was positively associated with MVPA in school time. CONCLUSION: Adolescents spent little time in PA during school. Future interventions should implement enjoyable activities at school.

Pattern of Sedentary Behavior in Different Periods of School Time of Brazilian Adolescents.

BACKGROUND: Sedentary behavior (SB) is related to unhealthy outcomes and is performed in many contexts, including school. The aim of this study was to identify sociodemographic, biological, and psychosocial correlates of SB performed at school in a sample of adolescents. METHODS: Adolescents provided information regarding sex, age, socioeconomic status, and psychosocial variables related to physical activity (self-efficacy, attitudes, perception of school environment, peer and parental support). Body fat was estimated using skinfolds, and maximum aerobic capacity with a 20 m shuttle run. Adolescents wore accelerometers and SB performed during class time, physical education (PE) classes, and recesses was estimated. RESULTS: Adolescents (N = 567, 53% female, 12.9 ± 5.3 years old) spent 67% of class time, 41% of PE classes, and 41% of recesses in SB. Girls spent more time in SB, and age was negatively associated with SB. Body fat was positively associated with SB in class time and PE classes. Peer support for physical activity was negatively associated with SB in class time, whereas attitudes related to physical activity were negatively associated with SB during PE classes and recesses. CONCLUSION: Adolescents spend long periods in SB at school, even during opportunities to be active like PE classes and recesses.

Sedentary behavior during school-time: Sociodemographic, weight status, physical education class, and school performance correlates in Brazilian schoolchildren.

OBJECTIVES: To investigate whether sedentary behavior during school-time is associated with gender, age, mother's education, having physical education classes, weight status, and academic performance. DESIGN: Cross-sectional study. METHODS: A sample of 571 children (7-12 years old) from five elementary schools in Florianopolis, South Brazil had their height and weight measured, and wore accelerometers during class time. Teachers completed a form to evaluate children's reading and writing skills. Parents provided sociodemographic and educational information. Data was analyzed using multilevel linear regression analyses. RESULTS: Children spent an average of 132min in sedentary behavior during school-time (64% of total school-time). Girls (137.5min), obese children (138.1min), older children (144.2min), and those who did not have physical education classes (140.2min) spent more time engaged in sedentary activities than their peers. Academic performance and mother's education were not associated with sedentary behaviors. CONCLUSIONS: Children spent most of their school-time in sedentary activities, with girls, older students, and obese students being even more sedentary than their peers. Physical education classes were a protective factor against excessive sedentary behavior in school. Interventions for reducing sedentary behavior during school-time could employ additional strategies to benefit the at risk groups. In addition, encouraging student's participation in physical education classes could minimize the time spent in sedentary behavior during school hours.