24h behaviours in children and adolescents

Background: While the influence of circadian rhythms on health outcomes has been increasingly studied, the role of rest-activity circadian rhythms in the development of pediatric obesity remains underexplored. Purpose: This study examined the associations between accelerometer-measured rest-activity rhythm characteristics and obesity among Czech children and adolescents. Methods: This study included a sample of 400 children (11.8±1.6 years; 56% girls) and 351 adolescents (16.2±1.4 years; 56% girls), who provided valid wrist-worn accelerometer data. The accelerometers ActiGraph wGT3X+ and GT9X Link were set to collect raw data continuously, 24 hours a day, for 7 consecutive days. For each of the circadian rhythm characteristics, participants were categorized into quartiles. The fat mass percentage (FM%) was assessed using bioelectrical impedance analysis method. Obesity was defined as exceeding the 85th percentile of FM%. The logistic regression analyses (adjusted for sex and age) were used to investigate the associations between the circadian rhythm characteristics and adiposity. Results: The analysis identified an association between the timing of the least active continuous 5-hour period (L5hr) and adiposity in children (OR = 1.40; 95% CI: 1.04–1.88) indicating a higher likelihood of obesity with later timings of these inactive periods. Conversely, no significant associations were found for other circadian rhythm metrics, including Relative Amplitude, Interdaily stability, Intradaily variability, Mesor, Amplitude, Acrophase, and Acrotime, M5hr, L10hr, and M10hr. Conclusions: The findings highlight the importance of the timing within the circadian cycle of physical inactivity in relation to excess adiposity among children. This study contributes to the growing evidence supporting the integration of circadian health into obesity prevention strategies for youth. Practical Implications: The observed association between the timing of circadian rhythm inactivity and obesity underscores the need for detailed future investigations. Funding: This study was supported by the research grant from the Czech Science Foundation (22-02392S).

Background: Physical activity (PA), sedentary behaviours and sleep are codependent, because the time allocated to one behaviour inevitably replaces the time spent on the others within 24 hours. These behaviours have individual associations with learning outcomes but have rarely been studied together as a composite whole. Purpose: The study examined the association of the 24-hour activity composition on arithmetic and reading fluency in children. Methods: Volunteered third-grade children in central Finland (N=208, mean age: 9.5 years, 51% girls) participated in the study. Light PA, moderate-to-vigorous PA (MVPA) and sedentary time (ST) were measured using hip-worn accelerometers (ActiGraph GT3X+) and sleep time and screen time with self-reported diaries for seven consecutive days. By combining accelerometer and diary data, a composition of 24-hour activity behaviours (sleep time, non-screen ST, screen time, light PA, MVPA) was formed. Arithmetic fluency was measured with four tasks from the FUNA dyscalculia test battery and reading fluency with the Sentence Verification Task, LUKSU. Linear mixed-effect models were fitted to the data. Results: The 24-hour activity composition was significantly associated with reading fluency, but not with arithmetic fluency. The ratio of sleep time to other activities was directly associated with reading fluency (β=0.73, p<0.05). Conclusions: Replacing time spent on any other activities with sleep may enhance reading fluency. Practical implications: In order to support reading fluency, parents should be educated about the important role of sufficient sleep in supporting children´s learning outcomes and encouraged to ensure that children get enough sleep. Funding: Finnish Ministry of Education and Culture.

Background: Although the independent association between sleep, sedentary behaviour, light-intensity physical activity (LPA), and moderate to vigorous physical activity (MVPA) with social-emotional and cognitive outcomes in youth is well established, no studies have quantitatively synthesised the association between 24-hour movement behaviour compositions with these outcomes. Purpose: This meta-analysis aimed to determine the association between 24-hour movement behaviour compositions and social-emotional and cognitive outcomes in youth. Method: A systematic literature search was conducted of five electronic databases using combinations of keywords for 24-hour movement behaviours, social-emotion and cognitive development, and children and youth. Effect sizes were calculated as the standardised absolute change in outcomes for a relative change in 24-hour movement behaviour composition. A random effect meta-analysis with a robust variance estimator was used to analyse the data. Results: Overall, 14 studies were identified and included in the meta-analyses. Results demonstrated that spending more time engaged in MVPA (t = 2.39, p = .041) and less time engaged in LPA (t = -2.92, p = .017) relative to other movement behaviours was favourably associated with social-emotional outcomes. Interestingly, spending more time sedentary (t = 3.21, p = .012) and less time engaged in LPA (t = -4.94, p = .001) relative to other movement behaviours was favourably associated with cognition. Conclusion: Twenty-four-hour movement behaviour compositions are related with social-emotional and cognitive outcomes in youth. Practical implications: Movement behaviour guidelines for youths should focus on recommending engaging in MVPA, getting sufficient sleep, and engaging in cognitively engaging sedentary behaviours to promote social-emotional health and cognitive development in children. There is no support for the benefits of engaging in LPA. Funding: MB, GT, KF, MO, & SG are funded by the Health and Wellbeing Centre for Research Innovation (HWCRI), which is co-funded by The University of Queensland and Health and Wellbeing Queensland.

Background: Differences in associations between movement behaviours and mental health outcomes have been reported in youth samples stratified for sex and race, suggesting potential differential susceptibility among socially marginalized youth. Purpose: To assess which combinations of moderate-to-vigorous physical activity (MVPA), screen time, and sleep were associated with best and worst mental well-being and mental ill-health in a sample of adolescents; and whether associations differed based on racial identity. Methods: Cross-sectional self-report data from a 2021-2022 cohort of Canadian secondary school students included 15,679 Racialized, 47,736 White, and 4,143 Multiracial youth. Associations between movement compositions with mental health status and interactions based on race were assessed with regression. Behaviour combinations where predictions were in the top 5% were deemed “Goldilocks” compositions. Results: Mean (SD) age was 14.8 (2.3) years. Race significantly modified the association with all mental health outcomes. Dose response gradients illustrate that the association between sleep duration and mental health is stronger for White youth than Racialized or Multiracial youth. At lower volumes of screen use, the association with mental health was also more negative among White youth. No major difference between racial groups was observed for the MVPA dose-response gradient. Goldilocks compositions were similar across racial groups and tended to support maximizing sleep and MVPA while minimizing screen use. Conclusions: Racialized youth appear to be accruing less benefits from similar amounts of sleep as White peers. Sleep quality is hypothesized to be a potential contributor to this difference. Practical implications: The whole day matters for the relationship between movement and health indicators. Promoting sleep quality, not just quantity, may be especially important for promoting health in racialized communities. Funding: Analyses were supported by an anonymous donation to the Children’s Hospital of Eastern Ontario to develop the Precision Child and Youth Mental Health Initiative.

Background: Optimal time distribution between physical activity, sedentary behaviors (SB), and sleep appears to be essential in obesity management strategies. However, the impact of reallocating time among these behaviors, collectively known as 24-hour movement behaviors, remains underexplored. Purpose: We estimated the theoretical effects of reallocating time between 24-hour movement behaviors on obesity indicators across different age groups. Methods: A pooled data meta-analysis of 9,818 participants from 11 observational studies were performed. To estimate the time spent in movement behaviors, we reprocessed and harmonized individual-level raw accelerometer-derived data. The compositional isotemporal substitution models estimated changes in body mass index (BMI) and waist circumference (WC) associated with time reallocation between moderate-to-vigorous physical activity (MVPA), light-intensity physical activity (LPA), SB, and sleep. We performed the analysis separately for children, adolescents, adults, and older adults. Results: Significant changes in BMI and WC were observed even with 10-minute reallocations and became more clinically relevant when 60 minutes were reallocated. The greatest increases in obesity indicators were found when MVPA was reallocated to other movement behaviors, while increasing MVPA was the best protection against obesity. The highest magnitude of the decrease in BMI and WC was observed when time spent in SB was substituted with other behaviors. Reallocating time away from sleep and LPA showed several significant changes, but no consistent pattern was observed. Conclusions: This investigation emphasizes the crucial role of MVPA in mitigating obesity risk across the lifespan. The findings also highlight the importance of substituting SB with low-intensity movement behaviors. Practical implications: This study suggests that even small increases in physical activity and replacing sedentary time can improve weight status across all ages. Such a lifestyle change can be feasible and sustainable for many people, including those with severe obesity. Funding: Czech Science Foundation (18-09188S and 22-02392S)

Background: Growing evidence highlights the significance of 24-hour movement behaviours (MB) in promoting the health of children and adolescents. However, limited research has focused on understanding how MB group together and how the behaviours change over the week. Purpose: This study examined transitions of 24-hour MB typologies between school and weekend days. Methods: A sample of 338 children and adolescents (aged 11–18 years) participated in a 7-day assessment of 24-hour MB using wrist-worn accelerometers. Time spent in moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), sedentary behaviour (SB), and sleep were assessed and used to identify typologies. MB typologies and their transitions were identified utilising compositional data analysis and latent transition analysis. Results: Three distinct typologies were identified across weekdays and weekends. The typologies were labelled as Active (69.6 min of MVPA, 303.4 min of LPA, 561.9 min of SB, 507.7 min of sleep), Average (39.4 min of MVPA, 257.6 min of LPA, 676.6 min of SB, 470.2 min of sleep), Inactive (25.4 min of MVPA, 220.8 min of LPA, 711.0 min of SB, 486.7 min of sleep). Active (Schooldays: 40.9%; Weekend: 40.8%;) and Inactive (Schooldays: 6.4%; Weekend: 24.6%) typologies remained stable over the week, however almost 18% of individuals from Average (Schooldays: 52.7%; Weekend: 34.7%) transitioned to the Inactive typology. Conclusions: Our study emphasizes the stability of certain MB patterns across school and weekend days. The transition of individuals from the Average to Inactive typology underscores the need for targeted interventions to promote PA and reduce SB among children and adolescents. Practical implications: Focus on maintaining healthy MB habits during the whole week could positively impact the overall health of children and adolescents. Funding: This contribution was supported by the grant agency at Palacký University Olomouc (reg. no. IGA_FTK_2024_008).