All humans sleep, some for longer than others. We all get tired and feel the urge to sleep after being awake for longer periods of time. There has been proven links with sleep disruption and some neurological disease such as Alzheimer’s where certain plaques build up in the brain which are normally cleared away during sleep. These plaques form due to oxidative stress, a term that describes the natural toxic by-products produced during metabolism called reactive oxygen species (ROS) or free radicals. These free radicals are damaging to all organs, and if not properly neutralised, can lead to cell death. Normally cleared by the body naturally, one theory is the build-up of these free radicals occurs during wakefulness and are cleared, particularly from the brain during sleep, however the data to support this is conflicting.
A recent study investigated the effect of sleep as an antioxidant in fruit flies. Several genetic mutations of these flies were studied all of which caused the flies to sleep less than normal. What they found was that these short sleeping flies were more sensitive to acute oxidative stress and had shorter survival times than longer sleeping flies.
They also reduced oxidative stress in the brain of other flies by overexpressing antioxidant genes. What they found in these flies was that sleep was reduced, possibly because there was no need to reduce the reactive oxygen species.
This may suggest that oxidative stress may induce sleep as it builds up, and in turn, sleep may function to defend the body against oxidative stress.
http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2005206
