Top of the page Stages of Sleep Topic OverviewSleep stages are divided into non-rapid eye movement (non-REM) and rapid eye movement (REM). Non-REM (NREM) sleep Non-rapid eye movement (NREM) sleep has 3 stages: Stage N1 occurs right after you fall asleep and is very short (usually less than 10 minutes). It involves light sleep from which you can be awakened easily..