Study Links REM and Deep Sleep to Lower Disease Risk

Greater amounts of REM and deep sleep are linked to lower risks of dozens of diseases, according to a new study published on September 17, 2026, in the journal PLOS Medicine. The research also found that sleeping less than five hours per night is associated with the highest disease risk.

The study analyzed data from 95,559 participants in the UK Biobank. Each person wore a wrist accelerometer for seven consecutive days and nights. Researchers used a deep-learning algorithm to calculate sleep stages, total sleep duration, wakefulness after sleep onset, and night-to-night sleep irregularity. Health records were then tracked for a median follow-up period of 8.9 years to test associations with over 1,000 disease outcomes.

Key Sleep Stage Findings

Greater REM sleep was associated with a lower risk of 83 different diseases. For every interquartile range increase in REM sleep-equivalent to 47.6 more minutes-the risk of specific conditions dropped significantly.

Greater amounts of deep sleep were linked to a lower risk of seven conditions, including type 2 diabetes and major depressive disorder. In contrast, greater sleep irregularity and more wakefulness after sleep onset were each tied to a higher risk of several conditions, such as anxiety and substance use disorders.

The Critical Sleep Duration Window

Total sleep duration showed a nonlinear relationship with disease risk for many conditions. The lowest risk was concentrated in a 6- to 8-hour window. People who slept less than five hours faced the greatest clinical vulnerability, with an increased risk of 37 different conditions.

The authors of the study, led by Shengzhi Sun of Capital Medical University in China, stated their findings provide additional evidence supporting the role of a 6- to 8-hour sleep duration as a health safeguard. "Maintaining a sleep duration of 6 to 8 hours can effectively reduce the risk of multiple diseases," they wrote, attributing the benefit likely to more favorable distributions of sleep stages.

Study Context and Limitations

The research highlights a gap in understanding how real-world sleep patterns relate to health. Self-reported sleep measures often show poor correlation with objective assessments, making studies like this one using accelerometer data valuable. However, as an observational study, this research cannot establish that sleep patterns directly cause changes in disease risk. It only identifies associations.

The findings are particularly relevant in China, where sleep quantity and quality are national health priorities. A 2026 China Sleep Health White Paper found the average surveyed person sleeps 6.97 hours per night, but 23% sleep less than six hours. Only 26% of respondents reported a consistent sleep schedule. The study's authors conclude their work offers new insights for health promotion and preventive practice, emphasizing the protective role of specific sleep stages and sufficient duration.