Adherence to 24-hour movement guidelines and associations with mental well-being: a population-based study with adolescents in Canada

Background Insufficient physical activity, excessive recreational screen time, and inadequate sleep pose health risks in school-aged children and adolescents. The Canadian 24-Hour Movement Guidelines for Children and Youth advocate for balanced daily movement behaviours. This population-level study in British Columbia (BC), Canada, examined the proportion of young adolescents following these guidelines and how adherence correlated with their mental well-being. Methods Using cross-sectional self-report data from 26,974 grades 6-8 children (48% girls, mean age = 13.31) who had completed the Middle Years Development Instrument (MDI) in BC in 2023, we calculated the percentages of children meeting physical activity (at least 1 h daily), sleep (9 + hours for 5- to 13-year-olds, 8 + for > 13-year-olds), and screen time (no more than 2 h daily) recommendations. Eight groupings were created, indicating how many and which movement behaviour guidelines were met: none, sleep only, physical activity only, screen time only, physical activity and sleep, physical activity and screen time, sleep and screen time, and all three behaviours. Mean differences in depressive symptoms, optimism, and satisfaction with life scores across categories were estimated through sex-stratified linear mixed models, adjusting for covariates. Results Four percent of adolescents met all recommendations, while 15% met none. Meeting some or all recommendations was associated with higher levels of optimism and satisfaction with life, and lower levels of depressive symptoms compared to meeting none. Beneficial effects were overall larger for girls, and largest for depressive symptoms among girls meeting all recommendations versus none (-1.05, 95% CI [-1.14, -0.96]). Conclusions Adherence to the Canadian 24-Hour Movement Guidelines was associated with higher levels of well-being, but most grades 6-8 adolescents in our study did not meet the recommendations. Given sex differences in meeting the movement behaviour recommendations, public health strategies need to consider targeted interventions aimed at improving adherence to these guidelines, particularly focusing on reducing recreational screen time and increasing physical activity.