Buffering the effects of work stress on anxiety and depression: a moderated mediation model of physical activity enjoyment and sleep disturbance in China

This study aimed to investigate the pathways linking work stress to anxiety and depression among a sample of full-time white-collar professionals (spanning various industries and organizational hierarchies) in China’s first-tier cities and to test the buffering role of physical activity enjoyment in this adverse process. A cross-sectional survey was conducted with 1,546 professionals in Beijing, Shanghai, and Guangzhou. A moderated mediation model was tested using the PROCESS macro (Models 4 and 59) to examine the mediating role of sleep disturbance and the moderating role of physical activity enjoyment. The results indicated that work stress was significantly and positively associated with both anxiety and depression (β = 0.184, p < 0.001) and sleep disturbance (β = 0.431, p < 0.001). Sleep disturbance, in turn, was positively associated with anxiety and depression (β = 0.126, p < 0.001). Sleep disturbance partially mediated the relationship between work stress and anxiety and depression (indirect effect β = 0.071, 95% CI 0.049, 0.094). Crucially, physical activity enjoyment significantly moderated the associations between work stress and anxiety and depression (β = -0.166, p < 0.001), between work stress and sleep disturbance (β = -0.081, p < 0.001), and between sleep disturbance and anxiety and depression (β = -0.031, p < 0.05). This moderation ultimately attenuated the strength of the overall indirect effect. The findings demonstrate that physical activity enjoyment is a key protective resource for mitigating the adverse mental health associations of work stress. This study extends the Effort–Reward Imbalance (ERI) and Stress-Buffering Models (SBM) and provides critical empirical evidence for workplace interventions, suggesting a strategic shift from emphasizing quantity of exercise to enhancing the quality of the exercise experience.