Make me ... stay awake.

The last in a three-part series presented by Michael Mosley. In this part Mosley looks at research which suggests we only need around 2 hours sleep a night. He experiments with trying to stay awake as long as he can. He meets Tony Wright who holds the world record for resisting sleep - 11 days and 11 nights; he now only sleeps for 2-3 hours a night and believes he functions much better as a result. We follow Mosley as he spends 36 hours awake in New York then has to surrender and go to sleep. He then tries to work out what sleep is actually for and if it is possible for us to go without it - research seems to suggest that the population varies in terms of how much sleep they can do without; 1 in 5 people can apparently function quite well with little or no sleep. Sleep deprivation is also thought to be a cure for depression. Mosley meets people who attempt to defeat sleep in marathons and competitions. However, sleep deprivation is also used as a method of torture and can create devastating mood swings in certain individuals. Mosley then tries out Modafinil, a medication which keep you awake.