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Sleep Facts

I recently came across a great list of sleep facts on the Pieces of Phour blog, and thought I would share it with you all. (The list was originated by Australia’s The National Sleep Research Project.)

Before I launch into some selections from the list, here are my additions to the sleep trivia collection. Interestingly enough, one of these facts is about Australians and sleep.

The following 5 facts are all taken from my book, Good Night: The Sleep Doctor’s 4-Week Program to Better Sleep and Better Health:

  1. 75% of people in Portugal stay up past midnight, the highest percentage of any country.
  2. 7 of the top 10 nocturnal areas are in Asia, led by Taiwan, where 69% turn in after midnight.
  3. The Japanese sleep less than anyone else on the planet, with 41% snoozing just 6 hours or less each night.
  4. Australians go to bed the earliest and sleep the longest. In a poll, nearly one-quarter of Australians say they go to bed by 10 p.m., and 31% said they average more than 9 hours of sleep every night. (Perhaps all this beauty rest is why Australians are so successful in Hollywood!)
  5. One of the loudest snores recorded in Guiness World Records was 93 decibels (120db is a jet engine), by Kare Walkert of Kumla, Sweden, in 1993.

Now, onto the other list:


(Short version, taken from the original 40-item list.)

  1. The record for the longest period without sleep is 18 days, 21 hours, 40 minutes during a rocking chair marathon. The record holder reported hallucinations, paranoia, blurred vision, slurred speech and memory and concentration lapses.
  2. Anything less than five minutes to fall asleep at night means you’re sleep deprived. The ideal is between 10 and 15 minutes, meaning you’re still tired enough to sleep deeply, but not so exhausted you feel sleepy by day.
  3. A new baby typically results in 400-750 hours lost sleep for parents in the first year.
  4. One of the best predictors of insomnia later in life is the development of bad habits from having sleep disturbed by young children.
  5. The continuous brain recordings that led to the discovery of REM (rapid eye-movement) sleep were not done until 1953, partly because the scientists involved were concerned about wasting paper.
  6. REM dreams are characterised by bizarre plots, but non-REM dreams are repetitive and thought-like, with little imagery — obsessively returning to a suspicion you left your mobile phone somewhere, for example.
  7. Some scientists believe we dream to fix experiences in long-term memory, that is, we dream about things worth remembering. Others reckon we dream about things worth forgetting — to eliminate overlapping memories that would otherwise clog up our brains.
  8. Scientists have not been able to explain a 1998 study showing a bright light shone on the backs of human knees can reset the brain’s sleep-wake clock.
  9. British Ministry of Defence researchers have been able to reset soldiers’ body clocks so they can go without sleep for up to 36 hrs. Tiny optical fibres embedded in special spectacles project a ring of bright white light (with a spectrum identical to a sunrise) around the edge of soldiers’ retinas, fooling them into thinking they have just woken up. The system was first used on US pilots during the bombing of Kosovo.
  10. Seventeen hours of sustained wakefulness leads to a decrease in performance equivalent to a blood alcohol-level of 0.05%.
  11. The 1989 Exxon Valdez oil spill off Alaska, the Challenger space shuttle disaster and the Chernobyl nuclear accident have all been attributed to human errors in which sleep-deprivation played a role.
  12. Exposure to noise at night can suppress immune function even if the sleeper doesn’t wake. Unfamiliar noise, and noise during the first and last two hours of sleep, has the greatest disruptive effect on the sleep cycle.
  13. The “natural alarm clock” which enables some people to wake up more or less when they want to is caused by a burst of the stress hormone adrenocorticotropin. Researchers say this reflects an unconscious anticipation of the stress of waking up.
  14. After five nights of partial sleep deprivation, three drinks will have the same effect on your body as six would when you’ve slept enough.
  15. Ducks at risk of attack by predators are able to balance the need for sleep and survival, keeping one half of the brain awake while the other slips into sleep mode.
  16. Feeling tired can feel normal after a short time. Those deliberately deprived of sleep for research initially noticed greatly the effects on their alertness, mood and physical performance, but the awareness dropped off after the first few days.
  17. Diaries from the pre-electric-light-globe Victorian era show adults slept nine to 10 hours a night with periods of rest changing with the seasons in line with sunrise and sunsets.
  18. As a group, 18 to 24 year-olds deprived of sleep suffer more from impaired performance than older adults.
  19. Experts say one of the most alluring sleep distractions is the 24-hour accessibility of the internet.
  20. The extra-hour of sleep received when clocks are put back at the start of daylight in Canada has been found to coincide with a fall in the number of road accidents.

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