Researchers found that sleeping too little was associated with elevated risk across a surprisingly wide range of conditions.
Sleeping less than five hours a night was associated with a higher risk of dozens of diseases in a large study that tracked nearly 100,000 adults for almost nine years. The analysis also found that people who spent more time in REM and deep sleep tended to have lower risks of several major conditions, suggesting that both sleep duration and sleep structure may be linked to long-term health.
Researchers analyzed 95,559 UK Biobank participants who wore wrist accelerometers continuously for seven days and nights. A deep learning algorithm estimated total sleep time, REM sleep, deep sleep, light sleep, wakefulness after sleep onset, and how much sleep patterns varied from night to night.
More REM Sleep Was Linked to Lower Disease Risk
Greater REM sleep was associated with lower rates of 83 diseases. Each additional 47.6 minutes of REM sleep was linked to a 26 percent lower rate of heart failure, a 46 percent lower rate of dementia, and an 80 percent lower rate of Parkinson’s disease during follow-up.
More deep sleep was associated with reduced risk of seven conditions, including type 2 diabetes and major depressive disorder. By contrast, greater night-to-night sleep irregularity and more wakefulness after falling asleep were associated with higher risks of several conditions, including anxiety and substance use disorders.
The study did not prove that these sleep patterns directly cause or prevent disease. Because the research was observational, other health, behavioral, or biological factors could contribute to the associations.
A Six to Eight Hour Window Stood Out
Total sleep time showed a nonlinear relationship with many health outcomes. For most of the conditions showing this pattern, the lowest risk was concentrated between six and eight hours of sleep per night.
People who slept less than five hours had the greatest overall vulnerability, with higher risks of 37 conditions. Across the full analysis, researchers identified 156 statistically significant associations between sleep patterns and newly diagnosed diseases after correcting for the large number of comparisons.
“Phenome-wide association analysis identified 156 significant associations between sleep patterns and incident diseases after Bonferroni correction.”
The authors also reported that sleep duration had significant nonlinear associations with 86 disease phenotypes. For 69 of them, the duration associated with the lowest risk fell within the same six to eight-hour range.
“Sleep duration exhibited significant non-linear associations with 86 disease phenotypes, with the minimum-risk duration for the majority of these conditions (69 phenotypes) precisely concentrated within a 6-8 hour window.”
Objective Sleep Tracking Adds Detail
Much previous sleep research has relied on people estimating how long and how well they sleep. Those reports do not always correspond closely with objective measurements, which can make it difficult to study how specific sleep stages and overnight disruptions relate to later health.
In this study, wearable data allowed researchers to examine several dimensions of sleep at once. Participants were then followed for a median of 8.9 years, and their health records were used to test associations with more than 1,000 disease outcomes.
The authors concluded that the pattern supports a sleep duration of roughly six to eight hours for middle-aged and older adults, while also pointing to a possible role for how that sleep is distributed among different stages.
“The findings provide additional evidence supporting the role of a 6-8 hours’ sleep duration as a health safeguard for middle-aged and older adults, likely attributable to more favorable distributions of sleep stages,” the authors say. “Maintaining a sleep duration of 6-8 hours can effectively reduce the risk of multiple diseases, providing new insights for health promotion and preventive practice.”
Reference: “Accelerometer-derived real-world sleep stages and risk of incident diseases: A UK Biobank cohort study and phenome-wide association analysis” by Jingsong Luo, Ruiyi Liu, Jie Yin, Wangnan Cao, Shengzhi Sun and Rui Chen, 17 September 2026, PLOS Medicine.
DOI: 10.1371/journal.pmed.1005213
Funding: National Natural Science Foundation of China, Beijing Municipal Science and Technology Commission, Chinese Institutes for Medical Research, Beijing
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