What Does Sleep Do For Us?
Although scientists are still trying to learn exactly why people need sleep, animal studies show that sleep is necessary for survival. Above all, sleep appears necessary for our brains to work properly. Too little sleep leaves us drowsy and unable to concentrate the next day. It also leads to impaired memory and physical performance and leaves us less able to carry out complex cognitive, motor or learning tasks. Some experts believe sleep gives neurons a chance to maintain themselves. Without sleep, neurons may become so overloaded by normal cellular activities that they begin to malfunction. Sleep also may give the brain a chance to exercise important neuronal connections that might otherwise deteriorate from lack of activity.
Deep sleep coincides with the release of several hormones, such as growth hormone in children and young adults. Many of the body’s cells also show increased growth and repair of damage from factors like stress and UV rays during deep sleep – making it truly a "beauty sleep." Slow waves in deep sleep seem to be particularly important for brain recovery during sleep and may be associated with improved performance and memory that results from sleep after learning. Staying up all night before an exam is not as helpful as studying and then “sleeping on it.”