Associations between leisure-time physical activity and sleep problems among 11 346 Danish adults: the moderating role of stress

Sleep problems constitute a significant public health issue. Previous studies have found that regular leisure-time physical activity has the potential to improve sleep quality. However, stress may influence both physical activity and sleep, acting as a potential moderator in this association. The aim was to examine cross-sectional associations between self-reported leisure-time physical activity and sleep problems, as well as the potential moderating role of stress. The study population consists of 11 346 Danish adults (age ≥16 years) from the national representative Danish Health and Morbidity Survey conducted in 2021. Associations between leisure-time physical activity and sleep problems were analysed using multiple adjusted logistic regression, which included an investigation of effect modification by level of self-perceived stress. Adjusted odds ratios (ORs) for experiencing sleep problems were 1.37 [95% confidence interval (CI): 1.20-1.56] among participants who were mainly sedentary during leisure time, and 0.81 (95% CI: 0.72-0.91) among those with moderate to vigorous physical activity level compared to those with light physical activity level. Within all strata of stress levels, higher physical activity was positively associated with lower odds of sleep problems. For example, in the high stress level stratum, ORs were 0.80 (95% CI: 0.63-1.03) and 1.64 (95% CI: 1.28-2.11) in participants who were moderately to vigorously physically active and sedentary, respectively, compared to those who were lightly physically active. Higher levels of leisure-time physical activity appear to be associated with a lower prevalence of sleep problems, even among individuals who experience high levels of stress.