Income as a Moderator of Physical Activity's Impact on Mental Health: Insights From the Korean Health Panel Study II

Regular physical activity (PA) benefits mental health, but most research focuses on Western and affluent populations, limiting generalizability. This study explored how PA's effects on mental health vary by household income in Korean adults.

Data from 8235 participants (55.2% female; mean age = 63.35 [15.20] y) in the Korea Health Panel Study II (2019-2020) were analyzed. PA (regular vs irregular) and household income (low, middle, and high) were assessed in 2019, and mental health outcomes (stress, depression, anxiety, and suicidal thoughts) were measured in 2020. Multinomial logistic regression and interaction analyses examined associations between PA, income, and mental health outcomes, controlling for covariates.

Regular PA reduced odds of high stress across income groups: low income (odds ratios [OR] = 0.61, 95% CI, 0.51-0.73), middle income (OR = 0.78, 95% CI, 0.66-0.93), and high income (OR = 0.64, 95% CI, 0.55-0.76). Regular PA also lowered odds of anxiety (OR = 0.64, 95% CI, 0.42-0.98) and depression (OR = 0.61, 95% CI, 0.44-0.85) in high-income groups. High-income participants showed reduced odds of suicidal thoughts (OR = 0.65, 95% CI, 0.43-0.98). Significant interactions between PA and income were observed for all outcomes (P < .001).

Regular PA and higher income independently and interactively reduce adverse mental health outcomes. Promoting PA and addressing income disparities are essential for effective mental health interventions and policies.