According to research done by a group led by Prof Maiken Nedergaard at the University of Rochester Medical Centre, New York, it was discovered that a network of microscopic fluid-filled channels in rats clear waste chemicals from the brain.

Prof Nedergaard added that this process occurs mostly when the brain is shut off. According to the good professor:

"You can think of it like having a house party. You can either entertain the guests or clean up the house, but you can't really do both at the same time."

Other research also revealed that a lack of sleep alters the way in which the genes in the body's cells behave.

Researchers at Surrey University in Guildford found that genes involved in inflammation seem to increase their activity when the body lacks sleep and it was believed that the gene was responding to the lack of sleep as if the body is under stress.

This, according to Dr Malcolm von Schantz, who was a member of the Surrey research team, could easily help explain the links between sleep deprivation and negative health outcomes such as heart disease and stroke.

Furthermore, research suggests that parts of the human brain may well be asleep when it is sleep-deprived.

This was illustrated by studies on whales and dolphins which show that when asleep they continue to use half of their brain to swim and come up to the surface for air, which a study on human patients showed similarly goes on in our brains.

As people became more sleep-deprived, parts of their brain became inactive while they were still awake.

The moral of the story: sleep is very essential and a lack of it is detrimental to good health and well-being.