Sleep is one of the richest topics in science today: why we need it, why it can be hard to get, and how that affects everything from our athletic performance to our income.

In a recent research on comparing death rates among more than 1 million American adults some revealing factors about sleeping patterns came out.

Studies show that people who sleep between 6.5 hours and 7.5 hours a night, as they report, live the longest.

And people who sleep 8 hours or more, or less than 6.5 hours, they don’t live quite as long. There is just as much risk associated with sleeping too long as with sleeping too short.

The big surprise is that long sleep seems to start at 8 hours. Sleeping 8.5 hours might really be a little worse than sleeping five!

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