Association Between Health-Related Physical Fitness and Depressive Symptoms in Chinese Adolescents: A Nationwide Cross-Sectional Study Under the Healthy China Initiative

Abstract

Objective: This study explores the relationship between health-related physical fitness and depressive states in adolescents and examines the influence of gender, age, and parental education.

Methods: A stratified and cluster sampling method selected 689 students (grades 7, 8, 10, and 11) from a Beijing middle school. After screening, 441 adolescents (12-18 years, 55.3% male) were included. Measurements included body composition (BMI), cardiopulmonary fitness (vital capacity), muscular strength/endurance (grip strength, sit-ups, standing long jump), and flexibility (sit-and-reach). Depressive states were assessed using the depression subscale of the Achenbach Youth Self-Report Scale (YSR). Data were analyzed using SPSS 24.0 with descriptive statistics, stratified analysis, and Pearson correlation.

Results: Cardiopulmonary fitness was significantly negatively correlated with depressive states (r = -0.346, p < 0.001), while grip strength showed a weak positive correlation with depression (r = 0.137, p = 0.003). Standing long jump exhibited a slight positive correlation with depression scores (r = 0.114, p < 0.05), but the effect size was negligible. BMI, sit-ups, and sit-and-reach showed no significant correlation with depression scores (p > 0.05). Stratified analysis revealed that females aged 15-18 had significantly higher depression scores than their male counterparts (p < 0.001) and were negatively correlated with cardiopulmonary fitness (r = -0.32, p = 0.002). Grip strength in males significantly increased with age (r = 0.62, p < 0.001), while in females, it stabilized after age 15 and showed no significant correlation with depression (p > 0.05).

Conclusion: Cardiopulmonary fitness is a key factor in adolescent mental health, with a stronger impact than muscular strength. Late-adolescent females are at higher depression risk, likely due to lower cardiopulmonary fitness and increased stress. Findings highlight the need for interventions improving cardiopulmonary fitness to support adolescent mental health.

Keywords: adolescents; correlation analysis; depression-related states; empirical study; health-related physical fitness; healthy China perspective.