Check your sleep tracker doing well in a key metric is linked to lower risk of dementia, heart failure and 81 other conditions

Your Oura ring or Apple Watch may holds secrets about your health that you didn’t even realize.There’s a lot wearables can tell us, from estimates of the calories we’ve burned to our heart rate variability to how much sleep we got last night.But hiding in that sleep data is a metric that may mean more than meets the eye.Researchers of a new study published in PLOS Medicine found that it could be a predictor of disease risk, including everything from dementia to type 2 diabetes.The team looked at sleep tracker data from over 95,000 people over the course of one week — then checked in on those people about nine years later.They found that more REM sleep — the stage when we dream — was associated with a lowered risk of 83 different diseases and conditions affecting nearly every part of the body.Those include blood and immune disorders, heart conditions, skin conditions, metabolic conditions such as obesity and type 2 diabetes, gastrointestinal conditions, bacterial and viral infections, mental health and substance use disorders musculoskeletal conditions such as arthritis, neurological conditions such as Alzheimer’s disease, and respiratory illnesses such as COPD.

The associations even extended to outcomes such as wheelchair dependence.The strongest associations were a lower risk of cannabis dependence (74% lower risk), Parkinson’s (72%), multiple sclerosis (52%), wheelchair dependence (49%), dementia (46%), Alzheimer’s (31%), and heart failure (26%).Deep sleep, the phase before REM, was also associated with lowered risk of seven conditions: anemia, type 2 diabetes, anxiety, major depressive disorder, arthritis, Parkinson’s, and sleep apnea.The best way to know how much REM sleep you’re getting is by getting a polysomnography (PSG) at a sleep clinic, where techs attach special sensors to detect brain waves, rapid eye movement, and temporary paralysis in the limbs that happens during REM.But sleep trackers do their best to estimate REM sleep by co...