re called "rapid eye movements" or REM periods. REM periods appear in phases of sleep in which the sleeper is dreaming. Three years later, two scientists, Eugene Aserinsky and Nathan Klietman, found many different characteristics, in the human body which occur during REM sleep. A couple of characteristics found during REM phases include the flow of the blood and the body temperature increases.
             A machine known as an electroencephalogram, EEG, is used to test brain wave activity. During sleep, four types of EEG's are being studied: Beta, Alpha, Theta, and Delta waves. The brain is animated or anxious during the Beta waves. These waves are the fastest of the four. Alpha waves are shown in the periods of meditation or relaxation. Drowsiness and light sleepers can be shown up in Theta waves. During deep sleeps, the Delta appears. Delta waves are the slowest waves of the four.
             We enter sleep cycles when we fall asleep. These cycles are repeatedly used severa
             ...