A total of 341,248 adults (mean age = 39.7 years; men: 48.3%) were included in the study, with a 15-year follow-up. Participants reported sleep duration and disturbances (difficulty falling asleep, easily awakened, or use of sleeping medication). Physical activity was classified into 4 levels: <7.5, 7.5-14.9, 15-29.9, and ≥30 metabolic equivalent hours per week (MET-h/week). To understand the joint associations of sleep patterns and physical activity with mortality, Cox proportional hazard models were conducted, with exposure variables combining sleep duration/disturbances and physical activity.
Compared with the reference group (sleeping 6-8 h/day), individuals who slept >8 h/day had higher risk for all-cause mortality (hazard ratios (HR) = 1.31, 95% Confidence Interval (95%CI): 1.25-1.37), CVD mortality (HR = 1.30, 95%CI: 1.17-1.45), and cancer mortality (HR = 1.13, 95%CI: 1.04-1.22). Short sleep duration was not associated with mortality risk. Increased risk of all-cause and CVD mortality was found in participants who had difficulty falling asleep (HR = 1.12, 95%CI: 1.07-1.18; HR = 1.16, 95%CI: 1.04-1.30, respectively), and used sleeping medication (HR = 1.26, 95%CI: 1.16-1.37; HR = 1.34, 95%CI: 1.10-1.62, respectively) compared with those who slept well. Long sleep duration and sleep disturbances were not associated with risk of all-cause and CVD mortality among individuals achieving a physical activity level of ≥15 MET-h/week, and in particular among those achieving ≥30 MET-h/week.
Long sleep duration, difficulty falling asleep, and use of sleeping medication were related to a higher risk of death. Being physically active at a moderate intensity for 25-65 min per day eliminated these detrimental associations.
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