People who get more REM sleep may have a lower risk of developing dozens of diseases, according to a large new study published September 17 in the open-access journal PLOS Medicine.
The research, led by Shengzhi Sun of Capital Medical University in China, analyzed data from 95,559 UK Biobank participants. Each participant wore a wrist accelerometer for seven consecutive days and nights, allowing researchers to objectively measure sleep stages—REM, deep, and light sleep—as well as total sleep duration, wakefulness after sleep onset, and night-to-night sleep irregularity. A deep-learning algorithm processed the data. Participants were followed for a median of 8.9 years, and their health records were checked against more than 1,000 disease outcomes.
The results were striking. Greater REM sleep—measured per interquartile range of 47.6 minutes—was associated with a lower risk of 83 diseases. The strongest links included heart failure (hazard ratio 0.74), dementia (hazard ratio 0.54), and Parkinson’s disease (hazard ratio 0.20). Greater deep sleep was linked to lower risk of 7 conditions, including type 2 diabetes and major depressive disorder. Meanwhile, greater sleep irregularity and wakefulness after sleep onset were each linked to higher risk of several conditions, including anxiety and substance use disorders.
Total sleep duration showed a non-linear relationship with disease risk. The lowest risk was concentrated in a 6-to-8-hour window. People sleeping less than 5 hours faced the most elevated vulnerability, with an increased risk of 37 conditions. As an observational study, the research cannot prove that sleep patterns directly cause disease, but the associations were robust after statistical correction. The authors note that phenome-wide association analysis identified 156 significant associations between sleep patterns and incident diseases.
Why It Matters for Your Brain
REM sleep is when your brain consolidates memories, processes emotions, and clears metabolic waste. The strong link between REM sleep and lower dementia risk (hazard ratio 0.54) suggests that prioritizing sleep quality—not just quantity—may be one of the most accessible ways to support long-term cognitive health. Deep sleep, meanwhile, is tied to physical restoration and glucose regulation, which may explain its connection to lower type 2 diabetes risk. Sleep irregularity and fragmented sleep emerged as independent risk factors, meaning that even if you get 7 hours, waking frequently or varying your schedule could undermine the benefits.
What You Can Do
- Aim for 6–8 hours of sleep per night, consistently.
- Keep a regular sleep schedule—going to bed and waking at the same time daily.
- Limit alcohol and caffeine close to bedtime, as both can suppress REM sleep.
- If you snore, gasp, or wake unrefreshed, talk to a doctor about a sleep study.
- Track your sleep with a wearable to spot patterns of irregularity or fragmentation.
Source: ScienceDaily Mind & Brain
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