4. Sleep Is An Essential Of Life—The Role Of Sleep In Life

Inasmuch as there are other lessons devoted specifically to the subject of sleep and its great significance, we'll touch upon sleep only briefly here.

Sleep is the condition under which the brain generates nerve energy with which to conduct body activities. The deeper the stage of sleep into which the body enters, the more efficiently can nerve energy be generated. There are five stages of sleep if we include the R.E.M stage, popularly called the dream stage, when there are rapid eye movements. Other stages are named after the brain wave frequency. The threshold stage of sleep is the alpha stage and the deepest stage is delta wave sleep.

As nerve energy is the spark of vitality for vigorous activity and high level function generally, adequate sleep is very essential to well-being.