Can physical activity eliminate the mortality risk associated with poor sleep? A 15-year follow-up of 341,248 MJ Cohort participants

Highlights

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  Long sleep duration (>8 h/day), difficulty falling asleep, and use of sleeping medication were related to a higher risk of all cause and cardiovascular death.

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  No association between short sleep (<6 h/day) and mortality was found. However, short sleep duration increased mortality risk among the least physically active group.

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  Physical activity may mitigate some of the mortality risks arising from poor sleep patterns and the risks of short sleep duration are exacerbated by physical inactivity.

Abstract

Background

This study examined the joint associations of sleep patterns and physical activity (PA) with all-cause, cardiovascular disease (CVD), and cancer mortality.

Methods

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). PA was classified into 4 levels: <7.5, 7.5–14.9, 15.0–29.9, and ≥30.0 metabolic equivalent hours per week (MET-h/week). To understand the joint associations of sleep patterns and PA with mortality, Cox proportional hazard models were conducted, with exposure variables combining sleep duration/disturbances and PA.

Results

Compared with the reference group (sleeping 6–8 h/day), individuals who slept >8 h/day had higher risk for all-cause mortality (hazard ratio (HR) = 1.307, 95% confidence interval (95%CI): 1.248–1.369), CVD mortality (HR = 1.298, 95%CI: 1.165–1.445), and cancer mortality (HR = 1.128, 95%CI: 1.042–1.220). 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 = 1.120, 95%CI: 1.068–1.175; HR = 1.163, 95%CI: 1.038–1.304, respectively), and used sleeping medication (HR = 1.261, 95%CI: 1.159–1.372; HR = 1.335, 95%CI: 1.102–1.618, 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 PA level of ≥15 MET-h/week, and in particular among those achieving ≥30 MET-h/week.

Conclusion

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/day eliminated these detrimental associations.

Graphical abstract