Longitudinal associations between exercise duration and sleep quality and poor sleep outcomes among college students: a latent growth curve modeling study

BACKGROUND: To investigate the effects of regular exercise on sleep quality and poor sleep outcomes, including bedtime procrastination, insomnia, and daytime sleepiness, among college students, and to examine the dynamic relationships between these outcomes and cumulative exercise duration over time. METHODS: A total of 687 college students were followed longitudinally at baseline and at 4 and 8 weeks after the intervention. Sleep-related outcomes were assessed using the Pittsburgh Sleep Quality Index (PSQI), Bedtime Procrastination Scale (BPS), Insomnia Severity Index (ISI), and Epworth Sleepiness Scale (ESS). Latent growth curve modeling (LGCM) was used to examine the developmental trajectories of sleep indicators as exercise duration accumulated over time, and cross-lagged panel modeling was further used to test the longitudinal predictive relationships among these variables. RESULTS: PSQI scores decreased linearly with increasing exercise duration (β = -0.88, P < 0.001), indicating progressive improvement in sleep quality. Bedtime procrastination (β = -0.72, P < 0.001), daytime sleepiness (β = -0.55, P < 0.001), and insomnia severity (β = -0.17, P < 0.05) also declined linearly over time. Baseline sleep quality and bedtime procrastination positively predicted subsequent changes in the later stages of the intervention (β = 0.41 and 0.65, respectively; P < 0.001). In addition, baseline bedtime procrastination positively predicted sleep quality at 4 weeks after the intervention (β = 0.20, P < 0.05). CONCLUSIONS: Accumulated exercise duration may effectively attenuate the deterioration of sleep quality among college students. Regular exercise may promote sleep health through multidimensional physiological and behavioral pathways and exert beneficial effects on bedtime procrastination, insomnia, and daytime sleepiness. For students with more severe sleep problems, individualized exercise programs combined with behavioral interventions may help sustain improvements in sleep outcomes.