The human brain is more active during sleep than during the day.
28
The average cat sleeps about 2/3 of the day.
203
Some people have a "natural alarm clock" allowing them to wake up when they want. This is actually caused by a burst of the stress hormone adrenocorticotropin.
15
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Studies show that the colder the room you sleep in, the more likely you are to have a bad dream.
28
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
193
The average person falls asleep in seven minutes.
115
The higher someone’s I.Q. the more likely they are to be sleep deprived.
29