Sleep Cycle

Sleep cycle

A period of sleep that varies (in humans) between 70 and 120 minutes and repeats itself until the the person wakes up. It is composed of several sleep stages, each with their own physiological characteristics and degrees of consciousness, which vary in duration throughout the entire sleeping period. The initial sleep cycles possess more N-REM sleep, and the later ones more REM sleep, which explains the increase of the amount of dreaming a person tends to experience in the last few hours of sleep.

Related Links: Sleep Stages