Sleeping on your stomach can induce weirder, scarier, and sexier dreams.
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The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
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In China, teachers allow children to sleep in class for around 20 minutes to help improve their learning.
13
Cows can sleep standing up, but they can only dream lying down.
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A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
Staying awake for 17 hours is the same for your body as drinking 2 glasses of wine.
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Blue light fends off drowsiness in the middle of the night, which could be useful to people who work at night.
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