People who sleep less than four hours dramatically increase their risk of dying early, possibly through heart disease, diabetes, high blood pressure, chronic stress, lower immunity, and overall more rapid aging.

new study published in JAMA Neurology looked at the relationship between REM sleep and earlier death in two large study groups, one consisting of 2,675 older men and the other of 1,386 middle-aged men and women. They followed both groups over time and looked at the relationship between sleep stages and causes of death.

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