Regular sleep may matter more than how long you sleep.
That’s the takeaway from a sweeping new study that linked six different sleep traits, including bedtime consistency and circadian rhythm stability, to 172 diseases across nearly every major body system. Using actigraphy data from more than 88,000 UK adults followed over 6.8 years, researchers found that poor sleep behaviors accounted for over 20% of the risk in nearly half of the conditions studied. The work, published in Health Data Science, offers the most comprehensive look to date at how objective sleep patterns shape long-term health.
Sleep Traits Influence Disease Risk Across the Body
The study tracked six distinct sleep traits using wrist-worn accelerometers:
- Nocturnal sleep duration
- Sleep onset timing
- Relative amplitude (day-night activity rhythm)
- Interdaily stability (sleep regularity)
- Sleep efficiency
- Nighttime waking frequency
Altogether, these traits were associated with 172 diseases across 13 physiological systems, including the circulatory, metabolic, respiratory, digestive, and neurological systems.
“Our findings underscore the overlooked importance of sleep regularity,” said Prof. Shengfeng Wang, senior author of the study from Peking University. “It’s time we broaden our definition of good sleep beyond just duration.”
Biggest Risks Tied to Sleep Rhythm, Not Duration
Among the most striking findings: poor sleep rhythm was often more predictive of disease than sleep duration. People with the lowest relative amplitude—a measure of circadian rhythm strength—had a 3.36-fold higher risk of age-related physical debility. Similarly, those with the most irregular sleep schedules had a 2.61-fold higher risk of gangrene and a 2.57-fold greater risk of liver cirrhosis if they regularly went to bed after 12:30 a.m.
Some common diseases with significant portions of their burden attributed to sleep traits included:
- Parkinson’s disease: 37.05%
- Type 2 diabetes: 36.12%
- Acute kidney failure: 21.85%
- Obesity: 31.63%
- Thyrotoxicosis: 30.45%
Challenging Assumptions About “Long Sleep”
The study also casts doubt on previous links between long sleep duration (≥9 hours) and cardiovascular disease. When using objective sleep tracking, only one disease showed increased risk among long sleepers. A likely explanation: nearly 22% of self-reported long sleepers were actually getting less than 6 hours of real sleep, suggesting they confused time in bed with actual sleep.
This misclassification skewed results in earlier studies and may explain false associations between long sleep and conditions like stroke and heart disease. When objectively short sleepers were excluded from the long-sleep category, the disease risks vanished.
Newly Discovered Sleep Links Replicated in U.S. Data
The team confirmed four previously unknown associations in an independent U.S. dataset (NHANES), including links between disrupted sleep rhythm and:
- Acute kidney failure
- Chronic obstructive pulmonary disease (COPD)
- Type 2 diabetes
- Depression
Inflammatory markers like C-reactive protein and leukocyte counts appeared to mediate these associations, suggesting biological plausibility for the sleep–disease connections.
Sleep Behavior as a Modifiable Risk Factor
One of the study’s most hopeful implications is that many of these risky sleep traits can be changed. Four of the six tracked traits are behavior-based. By simply improving bedtime consistency or reducing night-time phone use, individuals may reduce their long-term risk for major illnesses.
“These results provide a strong rationale for integrating objective sleep tracking into population health research,” the authors wrote. “And they highlight the importance of looking beyond just how much we sleep.”
With nearly 350 trait–disease associations uncovered and some risks rivaling those of obesity or smoking, this research repositions sleep regularity as a core pillar of preventive health—one we can often control.
Journal and DOI
Journal: Health Data Science
DOI: 10.34133/hds.0161
Article Title: Phenome-wide Analysis of Diseases in Relation to Objectively Measured Sleep Traits and Comparison with Subjective Sleep Traits in 88,461 Adults
Publication Date: June 3, 2025
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