Association Between Physical Activity Frequency and Depression Severity Among Adults in the United States With Mild...

Depression is a major contributor to global disease burden. While physical activity is often promoted as a protective factor, its independent association with depression severity remains unclear in population-based samples. This study examined the relationship between moderate-to-vigorous physical activity (MVPA) frequency and depression severity among U.S. adults with mild to moderate depressive symptoms.

We analyzed data from the 2015-2016 and 2017-2018 cycles of the National Health and Nutrition Examination Survey. Adults aged ≥18 years with Patient Health Questionnaire-9 (PHQ-9) scores between 5 and 14 were included. The outcome was total PHQ-9 score; the exposure was MVPA frequency, categorized as low (one to two days per week) and moderate/high (three or more days per week). Survey-weighted linear regression was used to adjust for demographic and clinical covariates.

Among 1,865 participants (representing 41.2 million U.S. adults), MVPA three or more days per week was not significantly associated with depression severity (β = 0.141, p = 0.48). However, higher income-to-poverty ratio (β = -0.173, p < 0.01) and older age (β = -0.012, p < 0.01) were linked to lower PHQ-9 scores. Racial/ethnic minorities reported significantly higher depression scores than Mexican Americans.

Physical activity frequency was not independently associated with depression severity. Socioeconomic and demographic factors were stronger predictors, highlighting the importance of addressing social determinants in depression interventions.