How much sleep do you need?
As you get older, you need less sleep - from about 16 hours a day as a baby, to less than 7 hours when you are over the age of 60. What happens if you go without sleep? Robert McDonald broke the world record in 1988 when he stayed awake for over 18 days. Long periods of sleeplessness can cause paranoia and even hallucinations at the time, but occasional sleep deprivation doesn't do any long-term damage.