Why we sleep - 'science-wise'

From animals to humans, everybody requires a good night sleep. However, the function of sleep still remains one of the greatest unsolved mysteries of science, say researchers.

While many theories suggest that sleep helps in brain "maintenance" - including memory consolidation and pruning- reverse damage from oxidative stress suffered while awake and promote longevity, none of them are well established.

Now, researchers from University of California, Los Angeles have come up with a new theory that sleep’s primary function is to increase animals'' efficiency and minimize their risk by regulating the duration and timing of their behaviour.

"Sleep has normally been viewed as something negative for survival because sleeping animals may be vulnerable to predation and they can’t perform the behaviors that ensure survival," Nature quoted Jerome Siegel, professor of psychiatry and director of the Centre for Sleep Research at the Semel Institute for Neuroscience and Human Behaviour at UCLA as saying, Siegel said.

"These behaviours include eating, procreating, caring for family members, monitoring the environment for danger and scouting for prey.

"So it’s been thought that sleep must serve some as-yet unidentified physiological or neural function that can’t be accomplished when animals are awake," he added.