NEW YORK, 26 Oct. - (ANA) - Not all stages of sleep are equal in terms of benefits for the brain.

 

Greater amounts of rapid eye movement (REM) sleep were associated with lower risks of 83 diseases, including dementia, Parkinson’s disease and heart failure, new research has shown.

 

Additionally, greater amounts of deep sleep were associated with lower risks of seven conditions.

 

That’s according to a study of 95,559 adults who wore wrist accelerometers continuously for seven consecutive days and nights. Researchers in China used deep-learning algorithms to analyze REM sleep, deep sleep, light sleep, total sleep duration, wakefulness after sleep onset and sleep irregularity.

 

They then looked at health records to assess associations with more than 1,000 diseases over a nearly nine-year follow-up period.

 

Greater REM sleep was associated with a significantly lower risk of several diseases, including Parkinson’s (80% lower relative risk), dementia (46% lower risk) and heart failure (26% lower risk).

 

Greater deep sleep was associated with lower risks of seven conditions, including Type 2 diabetes and major depressive disorder.

 

Disrupted sleep may sometimes be an early warning sign of disease rather than simply a cause, according to Dr. Chelsie Rohrscheib, head sleep expert at Wesper, a sleep analysis company in New York.

 

The researchers noted some limitations of the study. Because it was observational, it could only show an association and could not prove that increasing REM or deep sleep directly prevents disease.

 

As the participants were all from the UK Biobank, the study population was also less diverse and generally healthier than the overall population, so the findings may not apply equally to everyone, Rohrscheib noted.

 

Rohrscheib also cautioned that while wrist-worn sleep trackers are generally good at estimating sleep stages, they are not 100% accurate.

 

More research is needed to determine whether increasing REM or deep sleep can help prevent certain diseases, the researchers said.  - (ANA) -

 

AB/ANA/26 October 2026 - - -