More Than This Many Hours of Sleep Is Linked to Early Death, Scientists Find

A Nature study of 500,000 UK Biobank participants found sleep duration has a U-shaped link to biological aging and health risk.

The lowest risk appeared at about 6.4 to 7.8 hours of sleep per night.

Sleeping less than six hours or more than eight hours was associated with worse outcomes, including higher disease risk and all-cause mortality.

The authors note that long sleep may partly reflect existing illness, not just cause poor health.