---
title: "40 Mindblowing Facts About Sleep"
url: https://www.kickassfacts.com/40-mindblowing-sleep-facts/
date: 2017-01-12
modified: 2017-01-12
lang: en
author: "Admin"
description: "Here are 40 mindblowing sleep facts. 1-5 Sleep Facts 1. In medieval times it was common to have “2” sleeps per night. You would fall asleep for 4 to 5..."
categories:
  - "Fact List"
  - "Health"
image: https://www.kickassfacts.com/wp-content/uploads/2017/01/sleep-facts.jpg
word_count: 1478
---

# 40 Mindblowing Facts About Sleep

Here are 40 mindblowing sleep facts.

## 1-5 Sleep Facts

[![sleeping-man-medieval-times](https://www.kickassfacts.com/wp-content/uploads/2017/01/sleeping-man-medieval-times.jpg)](https://www.kickassfacts.com/wp-content/uploads/2017/01/sleeping-man-medieval-times.jpg)Image credit: British Library Royal 19 D III f. 458

1. In medieval times it was common to have “2” sleeps per night. You would fall asleep for 4 to 5 hours, wake up for 2 hours or so and fall back to sleep for another 3 to 4 hours. It’s been suggested that we may have evolved this way to tend to the [fire](https://www.kickassfacts.com/25-interesting-facts-about-fire/) in order to keep us warm and safe. - [Source](http://slumberwise.com/science/your-ancestors-didnt-sleep-like-you/)

2. 1-3% of the population is known as the sleepless elite. This group of people routinely gets 6 hours or less of sleep daily and remains totally functional. - [Source](http://healthland.time.com/2011/04/07/are-you-among-the-sleepless-elite-%E2%80%94-or-just-sleep-deprived/)

3. Astronauts must have good airflow around them when they sleep, otherwise, they could wake up oxygen-deprived and gasping for air because a bubble of their own exhaled carbon dioxide had formed around their heads. - [Source](http://www.esa.int/Our_Activities/Human_Spaceflight/Astronauts/Daily_life/)

4. The American Academy of Pediatrics recommends that [schools](https://www.kickassfacts.com/25-interesting-facts-about-schools/) delay the start of classes until 8:30 A.M. or later, better aligning school schedules with the biological sleep rhythms of adolescents during puberty. - [Source](https://www.aap.org/en-us/about-the-aap/aap-press-room/pages/let-them-sleep-aap-recommends-delaying-start-times-of-middle-and-high-schools-to-combat-teen-sleep-deprivation.aspx)

5. Giraffes only need 5 to 30 minutes of sleep in a 24 hour period. - [Source](http://www.thomsonsafaris.com/blog/sleeping-habits-of-giraffes/)

## 6-10 Sleep Facts

[![Marijuana](https://www.kickassfacts.com/wp-content/uploads/2017/01/Marijuana.jpg)](https://www.kickassfacts.com/wp-content/uploads/2017/01/Marijuana.jpg)

6. When you stop smoking [marijuana](https://www.kickassfacts.com/25-kickass-interesting-facts-about-marijuana/), you are going to experience a huge increase in your [dreams](https://www.kickassfacts.com/25-kickass-amazing-facts-about-dreams/) and their vividness due to your [brain](https://www.kickassfacts.com/30-kickass-amazing-facts-about-brain-part1/) trying to catch up on all the missed REM sleep for the next 2-7 weeks. - [Source](http://www.leafscience.com/2014/09/13/marijuana-rem-sleep-dreams/)

7. In order to discover that penguins sleep more deeply in the afternoon, scientists crept up on sleeping kind penguins at different times of the day and poked them with a stick until they woke up. - [Source](http://www.nature.com/news/2002/020925/full/news020923-3.html)

8. There is a [disease](https://www.kickassfacts.com/25-interesting-facts-about-diseases/) that takes away your ability to sleep. You sink into horrible psychosis and inevitably die over the course of a few months. There is no cure; there are no viable treatments. - [Source](http://gizmodo.com/fatal-familial-insomnia-the-brain-disease-that-stops-y-1695446513)

9. There are contact lenses worn during sleep that reshape your cornea. When you wake up, your vision is as good as it would be If you were wearing glasses or contacts during the day. They’re also used to treat myopia, hyperopia, and astigmatism. - [Source](https://en.wikipedia.org/wiki/Orthokeratology)

10. Having your alarm go off more than once in the morning doesn’t “slowly wake you up”, but actually makes it harder by causing you to restart the deep sleep cycle over and over again each time you hit snooze. - [Source](https://www.youtube.com/watch?v=0bJJGHcRRV4)

## 11-15 Sleep Facts

[![Finnish baby sleeping in cardboard](https://www.kickassfacts.com/wp-content/uploads/2017/01/Finnish-baby-sleeping-in-cardboard.jpg)](https://www.kickassfacts.com/wp-content/uploads/2017/01/Finnish-baby-sleeping-in-cardboard.jpg)Image credit: MILLA KONTKANEN

11. Finnish babies sleep in cardboard boxes. The government offers expectant mothers a maternity starter kit or a cash grant. 95% opt for the kit which includes a cardboard box that doubles as a crib. It has helped Finland achieve one of the world’s lowest infant mortality rates. - [Source](http://www.bbc.com/news/magazine-22751415)

12. During sleep cerebral spinal fluid flows through the brain on the outside of the brain’s blood vessels and that the CSF removes brain cell waste including amyloid beta protein. This flow only occurs during sleep. Amyloid beta protein buildup is involved in Alzheimer’s. - [Source](https://www.ted.com/talks/jeff_iliff_one_more_reason_to_get_a_good_night_s_sleep)

13. Modern people get similar amounts of sleep to people from pre-industrial times, but the extra exposure to artificial light means we sleep worse. - [Source](https://www.washingtonpost.com/posteverything/wp/2015/10/27/we-dont-need-more-sleep-we-just-need-more-darkness/?utm_term=.9570a8dd5cb6)

14. When asked, after 50 years of research, what he knew about the reason people sleep, William Dement, founder of Stanford University’s Sleep Research Center, answered, “As far as I know, the only reason we need to sleep that is really, really solid is because we get sleepy.” - [Source](https://en.wikipedia.org/wiki/William_C._Dement)

15. Sleep deprived drivers cause accidents because of ‘microsleep’ episodes during which they lose consciousness for up to thirty seconds. Most people do not realize that they had a microsleep episode and think they were awake all along. - [Source](https://en.wikipedia.org/wiki/Microsleep)

## 16-20 Sleep Facts

[![delayed sleep phase disorder](https://www.kickassfacts.com/wp-content/uploads/2017/01/delayed-sleep-phase-disorder.jpg)](https://www.kickassfacts.com/wp-content/uploads/2017/01/delayed-sleep-phase-disorder.jpg)

16. Delayed sleep phase disorder is often confused for insomnia. The person is able to sleep a full eight hours, just not when everyone else does. - [Source](https://en.wikipedia.org/wiki/Delayed_sleep_phase_disorder)

17. Fatal familial insomnia is a neurodegenerative disease eventually resulting in a complete inability to sleep. Many patients go six to nine months without sleep, during which time they develop dementia and become unresponsive. Death follows. - [Source](https://en.wikipedia.org/wiki/Sleep_deprivation)

18. Up to 70% of people will experience a hypnagogic jerk when falling asleep. A hypnagogic jerk is involuntary muscle spasm that occurs as a person is drifting off to sleep. The phenomenon is so named in reference to the hypnogogic state - the transitional period between wakefulness and sleep. - [Source](http://www.livescience.com/39225-why-people-twitch-falling-asleep.html)

19. Scientists have discovered why some people can thrive on less sleep than others. A particular gene variant is responsible, and those with it can also handle extended periods of sleeplessness better. - [Source](https://www.yahoo.com/news/scientists-discover-why-thrive-less-sleep-others-163712171.html?ref=gs)

20. There is something called sleep debt and if you do not reduce the debt you can experience worsened vision, impaired driving, and trouble remembering. Long-term effects include obesity, insulin resistance, and heart disease. - [Source](https://www.scientificamerican.com/article/fact-or-fiction-can-you-catch-up-on-sleep/)

## 21-25 Sleep Facts

[![soldiers-sleeping-under-tank](https://www.kickassfacts.com/wp-content/uploads/2017/01/soldiers-sleeping-under-tank.jpg)](https://www.kickassfacts.com/wp-content/uploads/2017/01/soldiers-sleeping-under-tank.jpg)Image credit: Manhhai/flickr

21. Tank crews don’t sleep under their tanks, as there is a story about a tank sinking in mud and crushing people. - [Source](http://www.bbc.co.uk/history/ww2peopleswar/stories/77/a4141577.shtml)

22. Sleep deprivation can temporarily act as an antidepressant. - [Source](https://www.scientificamerican.com/article/why-sleep-deprivation-eases-depression/)

23. LSD cured a [holocaust](https://www.kickassfacts.com/25-facts-about-holocaust/) survivor of [Auschwitz](https://www.kickassfacts.com/25-auschwitz-facts/)’s PTSD and allowed him to sleep for the first time in 30 years without [nightmares](https://www.kickassfacts.com/askus-why-do-we-have-nightmares-and-what-makes-us-afraid-of-our-own-thoughts/). - [Source](https://books.google.co.uk/books?id=H195mY-ZB_IC&pg=PA86&lpg=PA86&dq=Jan+Bastiaans+lsd&source=bl&ots=mgtK5KQNS5&sig=azigPL3CUNKtiG5DxTi0sab1d8g&hl=en&sa=X&ei=yyrkUs3MK7LKsQT0nIGYCw#v=onepage&q=Jan%20Bastiaans%20lsd&f=false)

24. A man named Dean Karnazes has a physiological advantage in that he doesn’t seem to have lactate threshold; thus was able to run 350 miles in under 81 hours without sleep. - [Source](https://www.theguardian.com/lifeandstyle/the-running-blog/2013/aug/30/dean-karnazes-man-run-forever)

25. The smell of [coffee](https://www.kickassfacts.com/25-interesting-facts-about-coffee/) reduces the stress caused by sleep deprivation and damage caused by stress. - [Source](http://www.livescience.com/2614-whiff-coffee-wake.html)

## 26-30 Sleep Facts

[![dog circle around sleep](https://www.kickassfacts.com/wp-content/uploads/2017/01/dog-circle-around-sleep.jpeg)](https://www.kickassfacts.com/wp-content/uploads/2017/01/dog-circle-around-sleep.jpeg)Image source: animalhub.com

26. [Dogs](https://www.kickassfacts.com/30-interesting-facts-dogs/) circle around because of their ancestors. The process of circling around before finding a place to sleep would mat down grass, as well as scare away any bugs or [snakes](https://www.kickassfacts.com/25-kickass-and-interesting-facts-about-snakes-part-1/) that might be in the place they want to sleep. - [Source](http://mentalfloss.com/article/29646/why-do-dogs-walk-circle-lying-down)

27. As much as 7% of the population has experienced waking from sleep and being totally paralyzed but aware as mind & body become out of sync in REM cycles. - [Source](https://en.wikipedia.org/wiki/Sleep_paralysis)

28. There is a rare sleeping disorder called Kleine–Levin syndrome that causes people to sleep for weeks at a time waking only to eat or go to the bathroom - [Source](https://globalgenes.org/kleine-levin-syndrome-a-rare-sleeping-disorder/)

29. Sleeping Beauty’s deep sleep was caused by a splinter of flax in her finger, and during her sleep, she was raped by a king (her father was a Lord). She gave birth to twins while enchanted and one sucked on her finger to remove the flax which woke her up. - [Source](https://en.m.wikipedia.org/wiki/Sleeping_Beauty#Basile.27s_narrative)

30. The “sleep” (eye discharge) in your [eyes](https://www.kickassfacts.com/30-kickass-interesting-facts-about-eyes/) when you wake up helps seal your eyes in an airtight fashion when they are closed; prevents tears from spilling onto your cheeks, and helps keep tears that coat your eyes from evaporating. - [Source](http://www.todayifoundout.com/index.php/2011/02/what-the-sleep-in-your-eyes-is/)

## 31-35 Sleep Facts

[![sleeping_male_lion](https://www.kickassfacts.com/wp-content/uploads/2017/01/sleeping_male_lion.jpg)](https://www.kickassfacts.com/wp-content/uploads/2017/01/sleeping_male_lion.jpg)

31. After a large meal, a male lion can sleep for up to 24 hours. - [Source](https://www.reference.com/pets-animals/long-lions-sleep-7823cbbff913083)

32. [Cats](https://www.kickassfacts.com/30-kickass-and-interesting-facts-about-cats/) sleep 70% of their lifetime; we [humans](https://www.kickassfacts.com/30-kickass-interesting-facts-about-humans/) only sleep 30%. - [Source](http://cats.about.com/od/amyshojai/a/understanding-your-sleepy-cat.htm)

33. In the early 1990s, 6-day long bicycle races were quite popular. The winner would be whoever rode the greatest distance in the 6 days. They would get extremely little sleep and hallucinate on the track. - [Source](https://en.wikipedia.org/wiki/Six-day_racing)

34. Street dogs in Moscow have learned to take the trains from the suburbs into the city for food during the day and then return to the safer, more comfortable suburbs to sleep at night. - [Source](https://en.wikipedia.org/wiki/Street_dogs_in_Moscow)

35. When former president Teddy Roosevelt died in his sleep in 1919, Thomas. Marshall, the sitting vice-president, said: “Death had to take Roosevelt sleeping, for if he had been awake, there would have been a fight.” - [Source](https://en.wikipedia.org/wiki/Theodore_Roosevelt#Death)

## 36-40 Sleep Facts

[![367px-Andre_in_the_late_](https://www.kickassfacts.com/wp-content/uploads/2017/01/367px-Andre_in_the_late_80s.jpg)](https://www.kickassfacts.com/wp-content/uploads/2017/01/367px-Andre_in_the_late_80s.jpg)Image credit: John McKeon

36. Andre the Giant died in his sleep while in [Paris](https://www.kickassfacts.com/30-kickass-interesting-facts-about-paris/) for his father's funeral. - [Source](https://www.reddit.com/r/todayilearned/comments/3trdq7/til_andre_the_giant_died_in_his_sleep_while_in/?ref=search_posts)

37. Seattle has a “tiny house” village that homeless residents can use to sleep, eat and shower. It costs residents $90 a month to cover utilities and is designed to help them get back on their feet. - [Source](http://learn.compactappliance.com/seattle-tiny-house-village/)

38. The movie ‘A Nightmare on Elm Street’ was based on news articles of Cambodian refugees refusing to fall asleep due to nightmares. Many of them ended up dying in their sleep of unexplained causes. - [Source](http://www.movies.com/movie-news/a-nightmare-on-elm-street-true-story/10075?wssac=164&wssaffid=news)

39. In 1993, an Army husband cut off his wife lover's head, dropped in her lap while she was in the hospital pregnant and said “Look, Diane, Glover’s here. He’ll sleep with you every night, only you won’t sleep at night.” - [Source](http://journaltimes.com/news/national/sergeant-convicted-in-beheading-murder/article_c8b22ce9-8bab-5f42-8d67-5815e44e7485.html)

40. In 1913 researchers kept dogs awake for several days, extracted spinal fluid, then injected this into other dogs which immediately put them to sleep - [Source](http://www.sleepdex.org/chemical.htm)