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.
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The record for the longest scientifically documented period without sleep is 264.4 hours (eleven days).
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Sleeping on the job is acceptable in Japan. It is viewed as exhaustion from working hard. Some people fake it to look committed to their job.
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The human brain is more active during sleep than during the day.
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You burn more calories sleeping than you do watching television.
348
People who sleep late have more mental stamina and can outperform early risers.
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47% of people have a nightmare at least once a month.
186
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
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