PURPOSE This study investigated the associations among sociodemographic factors, physical activity (PA) types and frequencies, and various mental health indicators among adolescents. METHODS Participants included 45,006 adolescents who answered the online 2024 Korea Youth Risk Behavior Survey. Mental health– related variables, such as perceived sadness and despair, suicidal ideation, perceived loneliness, and generalized anxiety disorder diagnosis, were analyzed in relation to sociodemographic factors. Associations with PA type and frequency were examined as well. The data underwent simple and multiple logistic regression analyses, and odds ratios with 95% confidence intervals were calculated. RESULTS First, sadness and despair perceptions significantly differed by gender, academic achievement, residence type, student classification, and study time. Adolescents who performed low-intensity PA ≥4 days per week and high-intensity PA 1–3 days or ≥4 days per week had significantly lower odds of experiencing sadness and despair. Second, suicidal ideation was significantly associated with gender, academic achievement, socioeconomic status (SES), residence type, urban vs. rural classification, student classification, and study time. Adolescents who engaged in low-intensity PA ≥4 days per week and high-intensity PA 1–3 days or ≥4 days per week displayed a significantly lower likelihood of suicidal ideation. Third, loneliness perceptions significantly varied by gender, academic achievement, economic SES, type of residence, urban vs. rural classification, student classification, and study time. Engaging in low-intensity PA ≥4 days per week was significantly associated with lower odds of perceived loneliness. Finally, the diagnosis of generalized anxiety disorder was significantly associated with gender, academic achievement, SES, residence type, student classification, and study time. Performing low-intensity PA ≥4 days per week and high-intensity PA 1–3 days or ≥4 days per week was significantly linked to a lower likelihood of a generalized anxiety disorder diagnosis. CONCLUSIONS Regular PA is an effective strategy for promoting adolescent mental health; specifically, appropriate exercise intensity and supportive environments for adolescents’ PA play a critical role in improving their mental health.
