Participants were 6070 school-children (aged 9-15 years) participating in a national health and fitness survey in 1985. Physical activity and depressed mood were assessed via self-report. Analyses were conducted separately by gender and school-level, and prevalence ratios adjusted for scholastic level, health status, smoking, alcohol consumption, residential arrangements and familial language.
Associations between physical activity and depressed mood were mixed however dose-response relationships were observed whereby increasing durations of total physical activity and discretionary sport in secondary boys were associated with decreasing prevalence of depressed mood (both Ptrend < 0.001). Further, increasing durations of physical education were associated with decreasing prevalence of depressed mood in primary girls (Ptrend = 0.02). No significant associations were observed for total physical activity or discretionary sport in primary and secondary girls. Associations were not mediated by overweight/obesity in girls.
Associations between physical activity and depressed mood varied by gender, school-level and the domain in which activity was assessed. Further research utilizing more accurate assessment of childhood physical activity and depression is required to clarify potential associations.