New studies into the importance of sleep for humans and animals are started to discover electrochemical events in our brains when we do and do not sleep.
An article called Why do we sleep? by the BBC asks some interesting questions and gives some answers about sleep. Below are some of excerpts.
Why do I sleep?
During the day brain cells build connections with other parts of the brain as a result of new experiences. During sleep it seems that important connections are strengthened and unimportant ones are pruned. Experiments with sleep-deprived rats have shown that this process of strengthening and pruning happens mostly while they sleep.
What happens when I don't get enough sleep?
It seems that a lack of sleep alters the way in which the genes in the body's cells behave ... "This could easily help explain the links between sleep deprivation and negative health outcomes such as heart disease and stroke."
Why is it hard to think when I am tired?
Research suggests that parts of the human brain may well be asleep when it is sleep-deprived. Studies on whales and dolphins show that when asleep they continue to use half of their brain to swim and come up to the surface for air.