Research
Mixed
Habitual sleep duration of less than 6 hours or greater than 9 hours is associated with a significantly increased risk of cardiovascular disease (CVD) and all-cause mortality compared to 7-8 hours of sleep.
Aim for 7-8 hours of sleep per night to minimize cardiovascular risk. Both sleeping less than 6 hours and more than 9 hours is associated with higher risks of heart disease and death. Prioritize consistent, adequate sleep duration as a key modifiable health factor.
GoodSupportsHIGH confidence
Overall, sleep duration is associated with mortality in a U-shaped fashion, with the highest risk found for short and long sleepers and the lowest risk in individuals who report average sleep durations of 7–8 hours.
Why this rating
Supported by multiple meta-analyses and large prospective cohort studies, though observational nature limits causal inference.
Source
Sleep duration, cardiovascular disease, and proinflammatory biomarkers
Michael A. Grandner et al. · Nature and Science of Sleep · 2013
DOI 10.2147/nss.s31063
narrative_reviewCited 239×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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