The Moderated Mediation Role of Depressive Symptoms and Physical Health in the Relationship Between Physical Exercise and Sleep Quality Among Emerging Adults.

Previous research has documented certain associations between physical exercise and sleep quality, yet little is known about the potential influencing mechanisms and boundary conditions underlying them. Thus, the present study aims to examine the potential mediating role of depressive symptoms and the moderating effect of physical health in this relationship. Using the individual-level survey data of 1613 emerging adults aged 18-25 from the China Family Panel Studies (Mage = 20.45 years, SDage = 1.32; 53.8% female), the common method bias test, descriptive statistics and correlation analysis, mediation effect analysis, moderation effect analysis, and simple slope test were sequentially performed using SPSS 27.0, with the significance level set at 5%. The results disclosed that depressive symptoms may play a partial mediating role between physical exercise and sleep quality among emerging adults, and physical health significantly moderated the association between physical exercise and depressive symptoms, indicating a stronger negative association among emerging adults with worse physical health compared to those with better physical health. In addition, exploratory analyses suggested that physical health may also moderate the associations between physical exercise and sleep quality, as well as between depressive symptoms and sleep quality. These findings suggest that emerging adults with lower physical health may often accompany higher depressive symptoms and poorer sleep quality, and also highlight the importance of actively engaging in physical exercise and developing regular exercise habits in daily life to effectively address this problem.