If you feel a bit ropey after a bad night's sleep, imagine how Randy Gardner, a teenager from California, felt after staying awake for 11 days. The effects of this voluntary insomnia included mood swings, disorientation, hallucination and memory loss. There was a point when Gardner was asked to repeatedly subtract 7 from 100, but stopped at 65 after completely forgetting what he was doing mid-task. Amazingly, he didn't touch a drop of coffee or any other stimulants during his time awake and relied on vigilant observers to keep him up. Sleep is one of the most mysterious things that we do, and we're still not entirely sure why we do it. What we do know, though, is that if you don't do it, you die. A condition known as Fatal Familial Disease completely robs its sufferers of the ability to sleep and, as there is no cure, sufferers die within three months. We don't really know why, we just know that, without sleep, the body just simply stops.
