And how they impact our lives
Sleep Stages an REM periods
REM sleep typically occupies 20–25% of total sleep in adult humans: about 90–120 minutes of a night's sleep. The first REM episode occurs about 70 minutes after falling asleep. Cycles of about 90 minutes each follow, with each cycle including a larger proportion of REM sleep.
REM stands for Rapid Eye Movement and most to all dreams occur during the REM period.