A large observational study presented in ScienceDaily reports that people who spent more time in REM sleep had lower risks of 83 different diseases. The findings come from tracking more than 95,000 individuals, making it one of the broadest looks yet at how sleep stages may relate to long-term health.
Among the conditions linked to less REM sleep were dementia, heart failure, and Parkinson's disease. The study's scope suggests that REM sleep may play a protective role across multiple organ systems, though the report does not establish causation.
As with any observational study, other lifestyle and health factors could influence the results. Still, the findings add to growing evidence that sleep quality—not just total duration—deserves attention in clinical care and prevention.