The impact of physical exercise on depression and anxiety among junior high school students in Sichuan, China: A cross-sectional study

Depression and anxiety among adolescents are global public health concerns. This study aims to explore the relationship between physical exercise and depression and anxiety among junior high school students in Sichuan, China, providing scientific evidence for mental health promotion. A cross-sectional survey was conducted from November 2024 to January 2025 among 6368 junior high school students (2526 from urban areas and 3842 from rural areas) in Sichuan using cluster sampling. The level of physical exercise was assessed using the International Physical Activity Questionnaire, and the total metabolic equivalent of task value was calculated. The depression-anxiety-stress scales were used to evaluate the levels of depression and anxiety. Descriptive statistics, Kendallz tau-b correlation analysis, and multinomial logit regression analysis were employed to explore the relationships. The findings of the study are presented as follows: The prevalence rates of depression and anxiety were 30.07% and 33.84%, respectively. Physical exercise was significantly negatively correlated with both depression (Tau B = -0.189, P < .001) and anxiety (Tau B = -0.159, P < .001); Physical exercise significantly reduced the risk of depression and anxiety (depression odds ratio (OR) = 0.870-0.975, anxiety OR = 0.944-0.977); and Students in higher grades had a significantly lower risk of depression and anxiety compared to those in lower grades (depression OR < 1, anxiety OR = 0.751-0.639). Physical activity has a protective effect against depression and anxiety in middle school students. Although the association is modest (with ORs close to 1), the findings are consistent, suggesting that physical activity should be incorporated as a complementary component within multi-faceted mental health initiatives both at school and at home.