Sleep duration and all-cause mortality: a systematic review and meta-analysis

Researchers combined results from 16 long-term studies involving about 1.38 million adults. They compared people who slept different amounts and tracked deaths from any cause. Sleeping less than about 7 hours was linked with a 10% higher death risk, while sleeping much longer was linked with about a 23% higher risk. The lowest risk was generally seen around 7 hours of sleep per night. These studies found links, but they cannot prove that sleep duration itself caused the deaths.

What this means for you: This does not mean you should force yourself to sleep exactly 7 hours or buy a sleep product. Aim for a regular amount of sleep that leaves you rested, and discuss persistent very short or very long sleep with a clinician because it can sometimes reflect illness.