Research
Mixed
Both short sleep (<7 hours) and long sleep (>8 hours) are associated with a significantly increased risk of all-cause mortality in a U-shaped pattern, with the strongest effects observed in young men.
Aim for 7-8 hours of sleep per night. Both sleeping less than 7 hours and more than 8 hours is linked to higher mortality risk, especially in younger men. While sleep quality itself may not be an independent risk factor after adjusting for lifestyle, maintaining a consistent and adequate sleep duration is a critical health lever.
GoodSupportsHIGH confidence
Significantly increased risk of mortality was observed both for short sleep in men (+26%) and in women (+21%), and for long sleep (+24% and +17%), respectively... The effect of sleep on mortality varied between age groups, with strongest effects in young men.
Why this rating
Large prospective cohort (N=21,268), long follow-up (22 years), adjusted for multiple covariates.
Source
Sleep and Mortality: A Population-Based 22-Year Follow-Up Study
Christer Hublin et al. · SLEEP · 2007
DOI 10.1093/sleep/30.10.1245
cohort · n=21268Cited 445×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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