The synergistic effects of diet and physical activity on sleep quality among Chinese adolescents: A comprehensive cross-sectional study

This study investigated the independent and interactive effects of dietary behaviors and physical activity on poor sleep quality among 15,059 Chinese adolescents. Using a cross-sectional design, we assessed sleep quality (Pittsburgh Sleep Quality Index, PSQI), dietary habits, and physical activity. Logistic regression and interaction analysis were performed to examine associations, adjusting for covariates. The prevalence of poor sleep quality (PSQI score ≥ 7) was 9.72%. Seven healthy dietary behaviors were identified as protective (e.g., regular diet, abstaining from alcohol; ORs=0.49-0.56). While physical activity showed no independent association, limiting screen-based sedentary screen time(≤2h/day) reduced poor sleep odds by 31% (OR = 0.69). Two significant interactions emerged: abstaining from alcohol combined with limiting sugary beverages synergistically reduced the odds of poor sleep quality by 42% (OR = 0.58), whereas the combination of healthy dining out and high physical activity was associated with a 181% increased odds of poor sleep quality (OR = 2.81). While healthy dietary patterns are strongly associated with better sleep quality, the interplay between behaviors is complex, demonstrating both synergistic protective association and antagonistic outcomes. Findings highlight the need for integrated lifestyle interventions that account for behavioral interactions in promoting adolescent sleep quality.