Mohsin Nawaz

The Facts About SLEEP! - The record for the longest period without sleep is 18 days, 21 hours, 40 minutes. Symptoms experienced included hallucinations, paranoia, blurred vision, slurred speech, memory and concentration loss.

- It's impossible to tell if someone is really awake without close medical supervision. People can unknowingly sleep with their eyes open..

- A new baby usually deprives it's parents of 400-750 hours of sleep in the first year.

- A bright light shone on the backs of human knees can reset your body clock but no-one knows why.

- Being awake for 17 hours straight is the equivalent of performing at a blood alcohol level of 0.05%.

- Unfamiliar noise, and noise during the first and last two hours of sleep, even if you don't wake up from it disrupts the sleep cycle.

- 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 in an unconscious anticipation of the stress of waking up.

- The light from a digital alarm clock can be enough to disrupt the sleep cycle even if you do not fully wake. The light turns off a "neural switch" in the brain, causing levels of a key sleep chemical to decline within minutes.

- To drop off we must cool off; body temperature and the brain's sleep-wake cycle are closely linked. That's why hot summer nights cause restless sleep.