Sleep is a “natural, temporary loss of consciousness” (Robinson, 1941) is necessary for our bodies to increase energy reserves and regenerate body cells and tissues. During sleep, the heart beats more slowly, breathing becomes slower, high-growth hormones, muscles relax and body temperature low. Newborns sleep almost continuously, gradually decreasing their need for sleep. In early childhood, 12 to 13 hours of sleep is generally required and this amount is reduced to about 8 hours in adulthood. After age 50, sleep is often characterized by frequent night time awakenings, sleep and sleep short lengths less overall (Brickler, 1990).
Many believe that the dream of being a low priority among the many daily activities engaged in is estimated that the world’s population is deprived of one hour less of sleep per night than is needed (Despertad!, 2004). Despite this vision of the night-time rest, sleep is a necessary, sophisticated process regulated by the brain. Operating as a 24 – hour clock, chemicals such as melanin, are released into the body to cause drowsiness. There are two main stages of sleep classified according to eye movement. The first is REM or rapid eye movement sleep is shallow, full of dreams.
There are four sub-REM sleep stages. The first sub-stage lasts 30 seconds to 7 minutes, during which time the muscles relax while the brain produces irregular wave activity. The second sub-stage lasts 20 percent of the night and brain waves become larger as the body is asleep. The next sub-stage is called delta sleep, where growth hormones peak, and cellular and tissue repair site.