Overview
- Researchers used week-long wrist accelerometer data from about 95,559 UK Biobank volunteers and linked those measurements to health records over roughly nine years to test associations with 1,049 conditions.
- More REM sleep at baseline was associated with lower risk for 83 conditions, including heart failure, dementia and Parkinson’s disease.
- Greater deep sleep was tied to reduced risk for seven illnesses, notably type 2 diabetes and major depressive disorder.
- Higher night-to-night irregularity and more wakefulness after sleep onset, markers of fragmented sleep, were linked to greater risk of psychiatric and metabolic problems such as anxiety and substance-use disorders, while habitual six- to eight-hour sleep showed the lowest overall risk.
- The study is observational and used accelerometers as a proxy for clinical sleep studies, so researchers say the findings show strong associations but cannot prove cause and they call for mechanistic, longitudinal and interventional work before changing public-health guidance.