Association of physical activity and sleep duration with depression in adolescents: A cohort study in Southwest China

To examine the relationship between PA, sleep duration and depressive symptoms among adolescents.

Data were drawn from the Coding Book of the Psychological Healthcare Guard Children and Adolescents Project of China. Adolescents' PA levels, sleep duration and depressive symptoms were assessed using self-reported questionnaires and the CES-D. Multiple linear and logistic regression models were applied to assess the independent and combined effects of PA and sleep on depression.

This study analyzed 191,260 adolescents with an average age of 14.8 years, 48.11 % of whom were female. The prevalence of depression was 25.28 %. Adolescents with depressive symptoms reported significantly shorter sleep durations (≤8 h on weekdays) and lower PA levels (P < 0.001). Longer sleep durations and higher PA levels were both correlated with lower depression scores (β = -2.94 to -3.28 for PA, -1.97 for sleep) and decreased odds of depression (OR = 0.60 to 0.63 for PA, 0.61 for sleep; all P < 0.001). A significant interaction was observed (P < 0.01), indicating that the combination of low PA and short sleep duration was associated with the highest risk of depression (OR = 2.135, 95 % CI: 1.901-2.403).

Higher levels of physical activity and longer sleep durations were independently linked to a reduction in depressive symptoms, underscoring the significance of both factors in maintaining mental health. The joint analysis revealed that the benefits of PA on reducing depression were attenuated by insufficient sleep, indicating a significant interaction between these lifestyle behaviors. However, limitations include the self-reported nature of PA and sleep data, and the cross-sectional design.