A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
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
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
The human brain is more active during sleep than during the day.
28
A new parent will lose about 1055.6 hours of sleep in the first year of their child's life - almost 44 days!
6
47% of people have a nightmare at least once a month.
186