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People who get more REM and deep sleep may have lower risks of a range of diseases, while sleeping less than five hours a night is associated with significantly higher disease risks, according to a new study published in PLOS Medicine.
Researchers led by Shengzhi Sun of Capital Medical University in China analysed sleep and health data from 95,559 UK Biobank participants who wore wrist accelerometers continuously for seven days and nights.
Using a deep-learning algorithm, the researchers assessed participants’ REM, deep and light sleep, total sleep duration, wakefulness after falling asleep and night-to-night sleep irregularity. Participants were followed for a median of 8.9 years, with health records used to examine links between sleep patterns and more than 1,000 diseases.
The study found that greater REM sleep was associated with a lower risk of 83 diseases. An additional 47.6 minutes of REM sleep, corresponding to the interquartile range, was associated with lower risks of heart failure, dementia and Parkinson’s disease, with hazard ratios of 0.74, 0.54 and 0.20, respectively.
Greater amounts of deep sleep were associated with lower risks of seven conditions, including type 2 diabetes and major depressive disorder.
In contrast, greater sleep irregularity and more time awake after initially falling asleep were associated with higher risks of several conditions, including anxiety and substance use disorders.
Total sleep duration showed a non-linear relationship with disease risk. For many conditions, the lowest risks were concentrated among people who slept six to eight hours a night.
Those sleeping less than five hours had increased risks of 37 conditions, the researchers found.
The findings are particularly relevant in China, where sleep quantity and quality have become a public health priority. The 2026 China Sleep Health White Paper reported that surveyed people in China slept an average of 6.97 hours a night, while 23% slept fewer than six hours. Only 26% reported maintaining a consistent sleep schedule.
The researchers noted that previous studies have often relied on self-reported sleep data, which may not accurately reflect actual sleep patterns. The use of wrist accelerometers in this study allowed researchers to objectively assess sleep characteristics in a large population.
The authors identified 156 significant associations between sleep patterns and newly diagnosed diseases after statistical correction.
They also found significant non-linear associations between sleep duration and 86 disease outcomes, with the minimum-risk duration for 69 of those conditions falling within the six-to-eight-hour range.
The researchers said the findings provide further evidence that maintaining six to eight hours of sleep may be associated with better health among middle-aged and older adults.
However, they stressed that the study was observational and therefore cannot establish that particular sleep patterns directly cause or prevent disease.