Joint and dose-dependent associations between aerobic and muscle-strengthening activity with depression: a cross-sectional study of 1.48 million adults between 2011 and 2017

Background: Research has shown that regular physical activity is key for the prevention and/or treatment of depression. However, epidemiological studies describing the associations between different physical activity modes (i.e., aerobic vs. muscle-strengthening exercise) with depression are limited. Methods: Cross-sectional analyses were conducted on pooled data from four U.S. health surveillance surveys (2011–2017). Validated survey items assessed self-reported moderate-to-vigorous-intensity physical activity (MVPA) and muscle-strengthening activity (MSA). Twenty groups were created, ranging from (a) “inactive” (0 MVPA min/week & MSA 0 times/week) to (xx) “most active” (≥300 MVPA min/week & MSA ≥4 times/week). Poisson regression with a robust error variance was used to assess prevalence ratios (PRs) of self-reported clinically diagnosed depression (outcome variable) across physical activity groups (exposure variables). Results: The sample contained 1,477,981 adults (≥18 years), of which 286,325 (18.0%) had depression. Compared to the reference group (i.e., no MVPA and no MSA), almost all physical activity combinations were associated with lower depression prevalence. Lowest prevalence of depression was shown for those combining sufficient MVPA–MSA (MVPA ≧300 min/week and MSA ≥2 times/week; adjusted prevalence ratio range: 0.54–0.63). All associations remained after stratification and/or adjustment for sociodemographic (age, sex, income, education), lifestyle characteristics (body mass index, self-rated health, smoking, alcohol), comorbidities (e.g., arthritis, diabetes, hypertension), and year of survey. Conclusions: A physical activity routine that includes both aerobic and MSA is likely to be optimal for the prevention of depression. Public health approaches targeting depression should endorse joint aerobic and MSA as key lifestyle modification strategy.