Key Sleep Metric Linked to Lower Risk of 83 Conditions, Study Finds
Increased time spent in REM sleep is associated with reduced risk of various diseases, including dementia and heart failure.
Data from wearable sleep trackers may offer insights into an individual's risk for a wide range of health conditions, according to a new study published in PLOS Medicine. Researchers found that the amount of time spent in Rapid Eye Movement (REM) sleep, the stage associated with dreaming, is linked to a lower risk of 83 different diseases and conditions.
The study analyzed sleep tracker data from over 95,000 individuals over one week and followed up with them approximately nine years later. The findings indicated that more REM sleep correlated with a reduced risk across numerous conditions affecting nearly every part of the body. These included blood and immune disorders, heart conditions, metabolic conditions such as type 2 diabetes and obesity, gastrointestinal issues, infections, mental health disorders, neurological conditions like Alzheimer's disease, and respiratory illnesses.
Significant associations were observed for a lower risk of cannabis dependence (74% lower risk), Parkinson's disease (72%), multiple sclerosis (52%), wheelchair dependence (49%), dementia (46%), Alzheimer's disease (31%), and heart failure (26%).
Deep sleep, another crucial sleep stage, was also linked to a reduced risk of seven conditions: anemia, type 2 diabetes, anxiety, major depressive disorder, arthritis, Parkinson's, and sleep apnea.
While polysomnography (PSG) in a sleep clinic provides the most accurate measurement of sleep stages, sleep trackers estimate REM sleep by analyzing movement, heart rate, and pulse variations. The study highlights the importance of overall sleep duration as well, noting that individuals sleeping six to eight hours per night had the lowest risk for many conditions, including type 2 diabetes, COPD, dementia, chronic kidney disease, and depression. Those sleeping less than five hours showed an increased risk for 37 conditions.
Furthermore, inconsistent sleep durations from night to night were associated with a higher risk of abdominal pain, anxiety, and major depressive disorder. REM sleep is vital for memory consolidation, problem-solving, mood regulation, and brain development in children. The typical sleep cycle involves four stages, with the REM phase gradually lengthening throughout the night, occurring four to six times per night.