Sleep - Wake Cycle

Abstract

Sleep is physiological unconsciousness and a necessary function of life and divided into five stages. These five stages are determined through the changes that observed through the electroencephalograph (EEG). The first four stages are called the non-rapid eye movement (NREM). In the next stage, a sudden burst of rapid eye movement is observed. Sleep cycles consists of 5-6 cycles of NREM and REM through the night. Sleep is the time when the body secretes many important hormones such as growth hormone, malatonin and cortisol. Finally, impact of sleep deprivation is associated with alterations of learning and memory, glucose metabolism, immune system and cardiovascular system.