Why Do We Need to Sleep?

We could give the easy answer to this question: Every living thing needs to rest. Sleep is a necessary period of deep rest that animals need in order to survive. But this doesn’t seem to dig deep enough into the subject. Saying we need sleep to survive doesn’t even begin to explain what sleep does for an animal.

To get to the next level of understanding sleep we have to admit that there are several theories on the subject. Different studies have shown various results so the final answer to our question has still not been nailed down. In fact, most text books, magazine and journal articles state that there really isn’t one theory that stands out above others.

If there is some common ground among the various ideas and theories it is this: our bodies not only slow down during sleep, some of the processes and systems even restore and repair during sleep. Scientists know that the chemical processes of the body change considerably during sleep, especially the balance of hormones and the ability of our bodies to fight off infection and illness (immune system). During these research projects, people who were kept from getting sufficient sleep seemed to be more susceptible to infection and illness. The immune system was weaker.

Brain activity changes during sleep as well. Some scientists believe that the key element of the brain – the neuron – is actually restored during sleep. Brain growth in young people may be seriously affected if these individuals are deprived of sleep. Some scientists theorize that our memories work better after sleep because of the restorative nature of sleep.

Some sociologists and anthropologists theorize that animals have always rested and slept because this gives them time to be safe, away from life-threatening situations. But it is difficult to inject scientific proof into this social theory.

One scientist is focusing on the fact that sleep may be the only time that brain activity slows down sufficiently to let the brain relax and recover. Apparently some of our body functions, such as heart beat and breathing, do slow down when we sit or lie down. But this rest isn’t sufficient for the brain to truly rest. This scientist’s theory is based on the fact that the rest of our body doesn’t really need sleep. However, he states, the brain does.

In connection with the idea that the brain must have sleep to restore basic elements – lack of sleep is one of the major causes of injury and illness. Our brains seem to require a certain period of unconsciousness so that it will function well during waking hours. In support of this theory, scientists note that the only constant work the brain does during sleep is keeping the heart and lungs working. All other functions cease, which leads to a very restful period for the brain. One of the pieces of evidence that scientists have uncovered in recent years is the question of how sleep allows the brain to rejuvenate, almost “recharge.” Sleep seems to be essential in helping maintain proper levels of energy usage in the body.