Type of Sleep
Sleep is a cycle of phases, a shift back and forth between rapid eye movement (REM) sleep and non-REM sleep. During REM sleep, memories and thoughts from the day are processed; it is the stage of sleep in which vivid dreams occur. During non-REM sleep, many restorative functions occur. In the deepest phase of non-REM sleep (known as slow-wave sleep), the brain recovers from its daily activities and hormones are released, which help the body rebuild itself from damage done during the day.