Why? Many Questions Answered

The origins and purposes of sleep are still not fully understood,
and experts have been arguing about them for millennia
Hippocrates, for instance, believed that sleep allowed
blood to retreat within the body, while Aristotle thought
that sleep was needed for digestion

The amount of sleep that each person needs depends on
his or her age, and without it, he or she can become irritable
and unable to complete normal tasks, while prolonged
periods without sleep can result in hallucinations and even
death Sleep, it seems, is necessary for our survival

There are many theories that attempt to explain the function
of sleep Some believe that sleep shuts down and repairs
neurons in the brain, allowing for the increased production
of hormones and proteins necessary to rejuvenate the emotional
and social functioning areas of our mind Sleep is also
thought to be vital for repairing the muscles and tissues of
the body, as well as the nervous and immune systems, and a
function for conserving energy It’s also believed that sleep
provides the necessary physical environment for the brain
to process information and organize our thoughts, and indeed,
things learned just prior to sleep are often more easily
remembered However, drugs such as alcohol alter certain
stages of sleep, reducing its rejuvenative benefit.s

It is thought that our present need for sleep stems directly
from the behavior of our ancestors, who would rest in
caves at night in order to avoid predators and because there
was little else to do during the hours of darkness As a result,
we have evolved to depend on sleep