Children's Physical Activity and Depression: A Meta-analysis

CONTEXT: Research regarding the protective effects of early physical activity on depression has abstract yielded conflicting results. OBJECTIVE: Our objective was to synthesize observational studies examining the association of physical activity in childhood and adolescence with depression. DATA SOURCES: Studies (from 2005 to 2015) were identified by using a comprehensive search strategy. STUDY SELECTION: The included studies measured physical activity in childhood or adolescence and examined its association with depression. DATA EXTRACTION: Data were extracted by 2 independent coders. Estimates were examined by using random-effects meta-analysis. RESULTS: Fifty independent samples (89 894 participants) were included, and the mean effect size was significant (r = -0.14; 95% confidence interval [CI] = -0.19 to -0.10). Moderator analyses revealed stronger effect sizes in studies with cross-sectional versus longitudinal designs (k = 36, r = -0.17; 95% CI = -0.23 to -0.10 vs k = 14, r = -0.07; 95% CI = -0.10 to -0.04); using depression self-report versus interview (k = 46, r = -0.15; 95% CI = -0.20 to -0.10 vs k = 4, r = -0.05; 95% CI = -0.09 to -0.01); using validated versus nonvalidated physical activity measures (k = 29, r = -0.18; 95% CI = -0.26 to -0.09 vs k = 21, r = -0.08; 95% CI = -0.11 to -0.05); and using measures of frequency and intensity of physical activity versus intensity alone (k = 27, r = -0.17; 95% CI = -0.25 to -0.09 vs k = 7, r = -0.05; 95% CI = -0.09 to -0.01). LIMITATIONS: Limitations included a lack of standardized measures of physical activity; use of self-report of depression in majority of studies; and a small number of longitudinal studies. CONCLUSIONS: Physical activity is associated with decreased concurrent depressive symptoms; the association with future depressive symptoms is weak.