Cows can sleep standing up, but they can only dream lying down.
745
The harder you concentrate on falling asleep, the less likely you are to fall asleep.
34
The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
15
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Lack of water is the #1 trigger of daytime fatigue.
148
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28