- 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.
- It's impossible to tell if someone is asleep or awake without medical intervention. People can take cat naps with their eyes open without even being aware of it.
- Anything less than five minutes to fall asleep at night means you are 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.
- A new baby typically results in 400-750 hours lost sleep for parents in the first year.
- One of the best predictors of insomnia later in life is the development of bad habits from having sleep disturbed by young children, such as having a child sleep with parents.
- The continuous brain recordings that led to the discovery of REM (rapid eye-movement) sleep were not done until 1953.
- REM sleep occurs in bursts totalling about 2 hours a night, usually beginning about 90 minutes after falling asleep.
- Dreams, once thought to occur only during REM sleep, also occur (but to a lesser extent) in non-REM sleep phases. It's possible there may not be a single moment of our sleep when we are actually dreamless.
- 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.
