Mysteries of Sleep: 45 Fascinating Facts About the Brain and Body at Rest

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1Brain While Sleeping

Brain While Sleeping

Sleep is the only time the brain has time to catch its breath. If it doesn’t, it will drown in its own biological debris, everything from toxic free radicals produced by hard-working fuel cells to spent molecules that are now useless.

2. Humans spend less time sleeping than any other primate. However, humans also sleep deeper than other primates. Because we sleep on the ground (no risk of falling from a tree) and are well-defended from predators, we can afford to get deeper, higher-quality sleep and so we don't need to sleep as long.

3. Astronauts need to sleep near air vents or risk carbon dioxide from their own lungs forming a bubble around their heads due to weightlessness.

4. Orthosomnia is a newly observed condition where some people are so obsessed with getting good sleep that they actually lose sleep over it.

5. Napping after learning leads to a significantly better recall rate of the learned material one week later.

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6Sleeping Beauty Syndrome

Sleeping Beauty Syndrome

Sleeping Beauty Syndrome is an extremely rare illness that causes episodes of being mostly asleep for weeks at a time. If awake during an episode, sufferers are confused about what is real and what is a dream. The condition appears in suffers in their teens and it resolves itself 10-15 years later.

7. About 1-3% of the human population is known as the sleepless elite. These people routinely get 6 hours or less of sleep daily and remain totally functional.

8. Research has found that when clocks are forwarded during daylight savings, people lose an hour of sleep and it therefore increases the risk of heart attacks by 25% on the following Monday. This risk reduces by 21% when clocks go back.

9. Sleep Apnea is highly underdiagnosed. It is estimated that 1 in 15 people have moderate to severe sleep apnea, causing daytime sleepiness and grogginess upon waking.

10. During sleep, cerebral spinal fluid flows through the brain on the outside of the brain's blood vessels and CSF removes brain cell waste including amyloid-beta protein. This flow only occurs during sleep. Amyloid beta-protein build-up is involved in Alzheimer's.

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Hypnagogia is the transitional stage between wakefulness and sleep. During this stage of sleep many hallucinations can occur, including the sensation of being bigger/smaller than yourself, floating, or falling.

12. Nowadays people get similar amounts of sleep to people from pre-industrial times, but we sleep worse due to extra exposure to artificial light.

13. Sleep deprivation beyond 24 hours causes visual, auditory, and sensory hallucinations, progressing to psychosis.

14. Playing “pink noise” (the sound of uniform static), while sleeping has been found to improve sleep quality and also help memory.

15. Sleep paralysis is the temporary inability to move that occurs right after falling asleep or waking up. Individuals remain aware during episodes, which frequently involve troubling hallucinations and a sensation of suffocation.

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16Second Sleep

Second Sleep

Hundreds of years ago most people used to go to sleep early, wake up for about an hour in the middle of the night and do various things, and then go back to bed for a 'second sleep.'

17. Optimal nap time is 7-8 hours after the wake-up time (early/mid-afternoon depending on when you wake up), for 20-45 minutes (to prevent sleep onset issues). Longer naps should be taken earlier in the day if you are trying to catch up on sleep debt.

18. The human brain remains half-awake when sleeping in a new environment for the first time.

19. Most people feel refreshed after a nap that lasts approximately 20 minutes. Longer naps can leave you feeling groggy because they require waking up from a deeper sleep.

20. Research suggests that people who take long naps during the day or sleep 9 or more hours at night may have an increased risk of stroke. Long nappers and long sleepers were 85% more likely to have a stroke. Those with poor sleep quality were 29% more likely to have a stroke.

21Benefits of Siesta

Benefits of Siesta

Siesta is a nap taken in the early afternoon, often after the midday meal. Such a period of sleep is a common tradition in some countries, particularly those where the weather is warm. Benefits of siesta include a boost in cognitive function and stress reduction.

22. In 2010, Spain held a siesta competition. It lasted for 20 minutes and contestants were awarded points on the quality of their sleep, their positions, their snores, and even their pajamas.

23. If you are sleep-deprived consistently and working then you are basically functioning at the level of a drunk person.

24. Placebo sleep is a type of sleep where you convince yourself that you slept well (even though you didn’t). It can actually trick your brain into thinking that you did sleep well.

25. In males, 80-95% of REM sleep is normally accompanied by partial to full penile erection.

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