A large study using wrist-worn sleep trackers has found that adults who spend more time in REM sleep face a lower risk of 83 different diseases, according to research covered by ScienceDaily and published in the journal PLOS Medicine.
The numbers
Researchers led by Jingsong Luo of Peking University tracked more than 95,000 adults who wore monitors for seven consecutive days and nights, measuring time spent in REM, deep and light sleep. Over the following nine years, the team cross-referenced health records covering more than 1,000 conditions. More REM sleep correlated with lower risk of 83 diseases, including heart failure, dementia, Parkinson's, Alzheimer's and multiple sclerosis, while more deep sleep was tied to lower risk of seven conditions, including type 2 diabetes and major depression.
Context
Sleeping less than five hours a night was associated with higher risk for 37 conditions, while the lowest overall disease risk was seen among people sleeping six to eight hours nightly — reinforcing existing sleep-duration guidance while adding new detail on which sleep stage matters for which disease, as Medscape noted in its coverage.
Reaction
Sleep researchers not involved in the study have cautioned that the wrist-tracker data shows correlation rather than proof that boosting REM sleep directly prevents disease, since underlying health conditions can themselves suppress REM sleep.
What's next
The authors say the dataset will be used to build risk-prediction tools based on wearable sleep data, and follow-up work is planned to test whether interventions that increase REM sleep — such as adjusting alcohol use or sleep timing — measurably reduce disease incidence.