Finding. A large-scale study tracking more than 95,000 people found that the amount of time spent in REM (rapid eye movement) sleep may be linked to the risk of 83 different diseases, including dementia and heart failure.
Detail. Participants who spent a greater share of their sleep in the REM stage showed lower risk across most of the 83 conditions examined. The findings suggest sleep stages may shape not just the quality of rest, but long-term health outcomes.
Scale. Given its size, the study stands out among research examining the relationship between sleep stages and chronic disease risk.
The study covered more than 95,000 participants and found an association between REM sleep and risk across 83 diseases: ScienceDaily, September 23, 2026.
This is an observational (correlational) study; the ScienceDaily summary does not demonstrate that REM sleep directly reduces disease risk (causation), only that an association was reported. How variables such as age and lifestyle were controlled for is not stated.
The journal, the authors, and the follow-up duration (years tracked) are not included in the ScienceDaily summary.