A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
47% of people have a nightmare at least once a month.
186
Dieters who sleep more take off more fat that those who sleep less.
159
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
44% of kids watch television before they go to sleep.
106
You burn more calories sleeping than you do watching television.
348
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