Eli5: Why do we end up more tired from sleeping longer than recommended amounts?

Question

Why is it when you sleep for 10-12 hours you end up more tired throughout the day than if you had 8 hours of sleep?

In: Biology

Answer 1

Hormones. The longer you sleep, the more “relaxing” hormones your body releases. If you sleep for 10 hours, you have more hormones (such as prolactin and melatonin) than you would have if you slept for 1 hour.