Research
Mixed
Sleeping less than six hours per night increases all-cause mortality risk by 13% compared to sleeping seven to nine hours, while sleeping six to seven hours increases risk by 7%.
Aim for 7-9 hours of sleep nightly. Sleeping less than 6 hours significantly raises your risk of death from all causes, and 6-7 hours also carries increased risk. Prioritize consistent sleep duration to protect long-term health.
GoodSupportsHIGH confidence
Investigating the link between sleep duration and mortality we find that at any given point in time, an individual that sleeps on average less than six hours per night has a 13 per cent higher mortality risk than an individual sleeping between seven and nine hours... Furthermore, an individual sleeping between six and seven hours per night has a 7 per cent higher mortality risk.
Why this rating
Based on a meta-regression analysis of existing studies, which is high-quality observational evidence, though not a randomized controlled trial of sleep deprivation for mortality.
Source
Why sleep matters -- the economic costs of insufficient sleep: A cross-country comparative analysis
Marco Hafner et al. · RAND Corporation eBooks · 2016
DOI 10.7249/rr1791
Meta-analysisCited 616×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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- Insufficient sleep (less than 6 hours) reduces workplace productivity by increasing absenteeism and presenteeism, resulting in approximately 6 lost working days per year compared to those sleeping 7-9 hours.Good
- Insufficient sleep imposes substantial economic costs on OECD countries, estimated at up to $680 billion annually in lost GDP across five major economies.Moderate
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