WHY DO PEOPLE NEED SLEEP?

Why do people need sleep?

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 benefits.

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.