Changes in Sleep Quality, Depressive Symptoms, and Sleep–Wake Preference Among University Students Participating in an Eight-Week Evening Aerobic Exercise Program: A Quasi-Experimental Study

Background/Objectives: Sleep disorders and depressive symptoms are common among college students and can negatively impact quality of life. Physical activity is recommended as a non-pharmacological approach to support sleep and mental health; however, findings regarding regular evening aerobic exercise in young adults are limited. This study aimed to examine changes in sleep quality, depressive symptoms and sleep–wake preferences among university students participating in an eight-week evening aerobic exercise program. Methods: This quasi-experimental study included 51 university students who were assessed before and after an eight-week intervention. Participants engaged in 60 min of aerobic exercise three days a week in the evening (between 6:00 PM and 10:00 PM). Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), depressive symptoms using the Beck Depression Inventory (BDI), and morning–evening type using the Morning–Evening Questionnaire (MEQ). Results: At the end of the eight-week period, a significant improvement was observed in total PSQI scores; significant changes were also noted in the subscales of sleep onset latency, habitual sleep efficiency, sleep disturbances, and daytime dysfunction (p < 0.05). A significant decrease was observed in BDI scores (median: from 17 to 9; p < 0.001), and the proportion of students with moderate-to-severe depressive symptoms decreased. A significant increase was also observed in MEQ scores (p < 0.001), which was found to be consistent with a shift toward an earlier sleep–wake preference. Conclusions: While these findings suggest that an eight-week evening aerobic exercise program may offer potential benefits in improving sleep quality and reducing depressive symptoms among university students, it is thought that changes in sleep–wake preferences may reflect short-term behavioral adaptation.