How It Works

Can you have too much sleep?

Yes. Oversleeping can cause headaches because you’ve slept too long without food and water. This is because headaches can be triggered by dehydration and low blood sugar. Depression and other undiagnosed medical problems can cause people to sleep more than average. This may be why studies find that people who sleep more than seven to eight hours have a shorter life expectancy. How much sleep we need varies among individuals and also varies over a lifetime. As babies we need more sleep than when we’re older.

Olivia Harwood, Science Museum