A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
You forget 90% of your dreams.
256
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
You burn more calories sleeping than you do watching television.
348
The strangers in your dreams are actually people that you've seen in real life.
50
People who sleep late have more mental stamina and can outperform early risers.
33