Association between physical activity and mental health (emotional and peer problems) in children and adolescents, a national follow-up study

BACKGROUND: While extensive evidence demonstrates the beneficial effects of physical activity on adult mental health, research examining these relationships in childhood remains limited and inconsistent. This study investigated the prospective associations between objectively measured physical activity and sedentary behavior at age 7 and emotional and peer difficulties at ages 11 and 14 using the UK Millennium Cohort Study. METHODS: Accelerometer-measured physical activity data from 6,434 participants at age 7 were analyzed. Emotional and peer problems were assessed using the Strengths and Difficulties Questionnaire (SDQ) at ages 7, 11, and 14. Multiple linear regression models examined associations between physical activity levels (sedentary, light, and moderate-to-vigorous [MVPA]) and mental health outcomes, adjusting for baseline SDQ scores and demographic and socioeconomic covariates. RESULTS: Greater MVPA at age 7 was significantly associated with fewer emotional problems at ages 11 (β = -0.004, 95% CI [-0.007, -0.002], p = 0.002) and 14 (β = -0.004, 95% CI [-0.007, -0.001], p = 0.007), and fewer peer problems at ages 11 (β = -0.005, 95% CI [-0.007, -0.003], p < 0.001) and 14 (β = -0.005, 95% CI [-0.008, -0.003], p < 0.001). Sedentary time and light physical activity showed no significant associations. Lower socioeconomic status and parental stress were associated with greater emotional and peer difficulties. CONCLUSIONS: Early childhood MVPA demonstrates protective effects against emotional and peer difficulties that persist into mid-adolescence. These findings provide evidence for the long-term mental health benefits of promoting MVPA in early childhood and highlight the importance of physical activity interventions for supporting healthy psychosocial development.