A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Quick naps not only improve your alertness, but they also help in decision making, creativity and sensory perception.
149
The average person falls asleep in seven minutes.
115
The human brain is more active during sleep than during the day.
28
Dieters who sleep more take off more fat that those who sleep less.
159
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
212