Physical Activity Levels and Depressive Symptoms in US Adults

AIM: Physical activity and sleep are modifiable depression risks, yet their integrated impact remains under-explored. We evaluated the association between moderate-to-vigorous physical activity (MVPA) and depressive symptoms, considering sleep duration and biological plausibility. METHODS: We analyzed 25,109 US adults (NHANES 2007 to 2020). Exposure was MVPA guideline adherence (≥150 min/week). Outcome was depressive symptoms (PHQ-9 ≥10); sensitivity analyses used ≥12 and ≥15 cutoffs. RESULTS: MVPA adherence was linked to 53% lower odds of depressive symptoms (aOR=0.47, 95% CI [0.35, 0.63]). Effects strengthened at higher thresholds (aOR=0.39 for ≥15), confirming robustness. Absolute risk reductions occurred across all sleep strata, particularly in short (-5.9 pp) and long sleepers (-8.2 pp). CONCLUSIONS: MVPA adherence is robustly associated with lower depressive risk, regardless of sleep duration. These protective effects are likely mediated by neuroinflammatory regulation and neuroplasticity. Promoting physical activity is a critical, scalable public health strategy.