Are one-year changes in adherence to the 24-hour movement guidelines associated with flourishing among Canadian youth?

Movement behaviours (e.g., physical inactivity, short sleep duration, high screen time) are associated with mental illness but less is known about the relationship between health behaviours and positive mental health constructs such as flourishing. This study examines if changes in adherence to the Canadian 24-Hour Movement Behaviour Guidelines for Children and Youth (moderate-to-vigorous physical activity (MVPA), total screen time (ST), sleep) are associated with changes in youth flourishing over one year. Students (N = 2292) were recruited from 12 secondary schools in Canada participating in the COMPASS study. Conditional change models were used to analyze two waves of longitudinal questionnaire data from 2016-17 to 2017-18. One-year change in adherence to the MVPA, ST, and sleep duration guidelines were modeled as predictors of flourishing adjusting for covariates. Models were stratified by sex. For males only, meeting MVPA guidelines both years was associated with higher flourishing compared to males not meeting guidelines (Est:0.87, SE:0.36, p = .01). Reducing ST was associated with higher flourishing for males only relative to other males who continued to exceed the ST guidelines (Est:2.23, SE:1.04, p < .03). Longer sleep duration had the most consistent association with greater flourishing among females (Est:1.02, SE:0.3, p < .001) and males (Est:0.93, SE:0.34, p < .006), highlighting sleep as a public health priority in the context of 24-hour movement behaviours. These findings contribute to increasing calls for research examining positive mental health constructs independent of mental illness.