Although all experts agree that sleep is of vital importance to proper human function, the exact purpose of sleep is not fully understood – though there are a number of theories.  Whether one theory is correct or if all of them are partially correct still remains to be seen.

 

 

The Restoration Process

 

Once possible purpose of sleep is to allow the body to heal and to grow.  This theory is supported by stage three and four during which the level of growth hormones increases and immune function experiences a change.  In addition, some studies have demonstrated that sleep deprivation leads to a decrease in the function of the immune system.  At the same time, there is no evidence that sleep deprivation causes problems with the muscles, the heart, or any other organs. 

 

The Development Process

 

Other theories revolve around the importance of sleep as it relates to development.  This is supported by the fact that people who experience sleep deprivation during the earlier stages of their lives tend to have more behavioral problems and experience permanent sleep disruption later in life.  In addition, there is evidence that lack of sleep during the early part of life can result in a smaller brain mass and an excessive amount of neuronal cell death. 

 

Processing Memories

 

Another possible purpose of sleep is to process memories.  Many of those that support this theory also believe that processing memories is the reason why we experience dreams when we sleep.  This theory is further backed by experiments in which subjects were provided new information right before going to sleep.  These studies found that the subjects retained the information better after sleep than if they did not go to sleep after leaning the new information.  When it came to rote memorization, on the other hand, getting sleep after memorizing the information did not have an impact on recall.

 

Metabolization

 

Another theory is that sleep provides the body with time to metabolize and process the nutrients that are obtained during the waking hours.  This theory actually takes an opposite approach and questions why we wake more than it questions why we sleep.  Under this theory, we simply wake in order to keep the body out of danger and to feed it in order to continue sleep.

 

Preserving the Body

 

Another theory states that we sleep in order to preserve the body.  Since it is not necessary to eat 24 hours per day or to perform other necessities, sleep provides a time for the body to stay out of the way of harm and to prevent them from falling prey to other organisms that are stronger.  Hence, sleep is really done as a matter of safety.  One flaw in this theory is the fact that the brain actually becomes disengage from its surroundings while sleeping, which actually puts the body in greater danger.  In addition, it does not explain the problems with cognitive ability, memory, and other issues associated with a lack of sleep.  In addition, we experience a need to sleep by feeling drowsy and this need is not driven by the desire to escape from harm.