Physical Activity and Depressive Symptoms in Adult Women: A Cross-Sectional Study on the Mediating Role of Perceived Stress

This cross-sectional study aimed to assess the relationship between the level of physical activity and the severity of depressive symptoms in adult women, taking into account the mediating role of perceived stress and differences in this relationship across levels of depressive symptom severity. The study included 200 women aged 18–65 years. Physical activity was assessed using the International Physical Activity Questionnaire (IPAQ), depressive symptom severity was measured with the Beck Depression Inventory (BDI), and perceived stress was evaluated using a standardized stress scale. Descriptive statistics, non-parametric tests, hierarchical regression, mediation analysis with bootstrapping, and quantile regression (Q25, Q50, Q75) were applied, controlling for selected sociodemographic variables. The results showed that perceived stress was the strongest predictor of depressive symptom severity. Physical activity was not a significant independent predictor of depression after adjustment for stress; however, it demonstrated a significant indirect effect through stress reduction. Quantile regression analysis revealed that the protective effect of physical activity was more pronounced in the lower and middle quantiles of depressive symptom severity and attenuated at higher levels of severity. These findings indicate that the relationship between physical activity and depressive symptoms is predominantly indirect and conditional, supporting the integration of physical activity promotion with stress-reduction–focused interventions.