Research
Mixed
There is a linear, dose-response relationship between longer sleep duration and increased mortality risk, with significant risk increasing at sleep durations >9.5 hours.
Your risk of mortality increases linearly as you sleep more. The data suggests significant risk begins to appear when you sleep more than 9.5 hours. Sticking to 7-9 hours minimizes this specific risk.
GoodSupportsHIGH confidence
Longer sleep duration was significantly associated in a gradient fashion with increased mortality (coefficient = 0.120, P <.0001... The 95% CIs of prediction curves were greater than 0 beginning at a sleep duration of >9.5 hours.
Why this rating
Meta-regression of multiple datasets showing a consistent linear trend.
Source
Long sleep duration and health outcomes: A systematic review, meta-analysis and meta-regression
Maki Jike et al. · Sleep Medicine Reviews · 2017
DOI 10.1016/j.smrv.2017.06.011
Meta-analysis · 137 studiesCited 772×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Long sleep duration (defined as >8 or >9 hours depending on the study) is significantly associated with increased all-cause mortality and incident cardiovascular disease, stroke, diabetes, and obesity compared to normal sleep duration.Good
- Long sleep duration is NOT significantly associated with incident hypertension, and evidence for depression and dyslipidemia is insufficient.Good
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