Research

Mixed

Short sleep duration (<6 hours) is significantly associated with higher body mass index, unmarried status, and poorer physical and mental health scores, suggesting it acts as a marker for adverse lifestyle and comorbidities rather than a direct causal risk factor.

If you sleep less than 6 hours, look at your lifestyle and health context, not just the clock. This study shows short sleep is strongly linked to being unmarried, having a higher BMI, and reporting poorer physical/mental health. Instead of stressing about sleep itself, address these underlying factors: manage stress, maintain a healthy weight, and check for underlying health issues. Sleep duration here acts as a signal of broader life stressors.

GoodQualifiesHIGH confidence
For short sleep duration, there were significant, consistent associations in both samples for unmarried status... body mass index... and Short Form-36 physical... and mental... scores.
Saverio Stranges et al. · American Journal of Epidemiology · 2008

Why this rating

Large sample sizes (n=6,472 UK, n=3,027 US) and consistent findings across two distinct populations increase reliability, despite cross-sectional design.

Source

Correlates of Short and Long Sleep Duration: A Cross-Cultural Comparison Between the United Kingdom and the United States: The Whitehall II Study and the Western New York Health Study

Saverio Stranges et al. · American Journal of Epidemiology · 2008

DOI 10.1093/aje/kwn337

cross_sectional · n=9499Cited 345×
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DOI resolved against Crossref · corpus check 2026-06-10

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