The health diet as a mediator in relationship between stress and sleep quality of college students with physical exercise as a moderator

With the development of society, contemporary young people, especially college students, are facing increasing levels of stress. Stress is often associated with poor sleep quality in individuals, but the underlying mechanisms between these two factors need further exploration. Therefore, this study aims to investigate the relationship between stress and sleep quality among college students, with stress as the independent variable, sleep quality as the dependent variable, healthy diet as the mediating variable, and physical exercise as the moderating variable, to further elucidate the underlying connections between stress and sleep quality in college students. A total of 4090 college students (1503 males and 2587 females; mean age 19.05 ± 1.16 years) were included in this study. Data on stress, healthy diet, physical exercise, and sleep quality were collected through a cross-sectional subjective survey. The basic characteristics of the variables were described using SPSS, and correlation analyses were performed. Finally, a moderated mediation model was constructed using the PROCESS macro. The study found that stress was significantly negatively correlated with healthy diet (r = -0.162, p < 0.001) and sleep quality (r = -0.492, p < 0.001) among college students. Healthy diet mediated the relationship between stress (β = -0.161, SE = 0.015, p < 0.001) and sleep quality (β = 0.160, SE = 0.014, p < 0.001) among college students. Physical exercise significantly moderated the relationship between stress and healthy diet (β = -0.040, SE = 0.015, p < 0.01). This study further elucidated the mechanisms underlying the relationship between stress and sleep quality among college students by incorporating behavioral variables (healthy diet and physical exercise). It is recommended that college students actively engage in physical exercise, which can help alleviate stress, promote healthy eating, and thereby improve sleep quality.