The interplay of physical activity, sleep, and chronotype on physical and mental health in Italian university students: a moderated mediation analysis.

BACKGROUND: Physical and mental health are receiving increasing attention among university students. This study aims to evaluate the relationship between physical activity level, chronotype, and sleep quality in influencing physical and mental health in a sample of 691 active Italian university students. METHODS: Participants completed the GSL-TPAQ, MEQ, PSQI, and SF-12 questionnaires and were divided into three categories based on physical activity level (low, medium, high). A three-way ANCOVA assessed the main effects of physical activity, chronotype, and sleep quality on physical and mental health. A moderated mediation model tested whether sleep quality mediated the relationship between chronotype and health, and whether physical activity moderated the effect of sleep quality on health. RESULTS: A three-way ANCOVA revealed that high physical activity, morningness, and good sleep quality were associated with better mental health. Specifically, students with high physical activity reported higher mental health (43.23 ± 8.97 a.u.) than those with low activity (40.65 ± 10.21 a.u.; p < 0.05). Morning-types reported better mental health (43.6 ± 9 a.u.) compared to evening-types (39.08 ± 10.05 a.u.; p < 0.001), and good sleepers scored significantly higher on mental health (43.64 ± 9.04 a.u.) than bad sleepers (37.7 ± 9.68 a.u.; p < 0.001). Good sleepers also had better physical health (52.55 ± 5.32 a.u.) than bad sleepers (50.14 ± 5.97 a.u.; p < 0.001). A moderated mediation model confirmed that sleep quality mediated the relationship between chronotype and mental health (indirect effect: B = -0.08, 95% CI [-0.12, -0.04]), with morningness associated with better sleep, and in turn, better mental health. Physical activity significantly moderated this effect: the index of moderated mediation was significant for medium activity (Index = -0.04, 95% CI [-0.08, -0.01]) and high activity (Index = -0.04, 95% CI [-0.07, -0.01]), suggesting that individuals with medium and high activity levels benefit most from the protective role of sleep in the chronotype-mental health pathway. CONCLUSION: These findings underscore the need to promote both good sleep hygiene and regular, sustained physical activity to support mental well-being among university students, especially those with an evening chronotype or bad sleep quality.