A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
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
You forget 90% of your dreams.
256
Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
240
Lack of water is the #1 trigger of daytime fatigue.
148
If you hold farts in during the day, they'll just come out when you sleep.
16
"Dysania" is the state of finding it hard getting up out of bed in the morning.
33