REM (rapid eye movement) sleep is a stage of sleep characterized by rapid eye movement, relaxed muscles, irregular breathing, elevated heart rate, and increased brain activity
. During REM sleep, your eyes move rapidly behind your closed eyelids, your heart rate speeds up, and your breathing becomes irregular
. This stage is associated with dreaming and plays a role in memory consolidation, emotional processing, brain development, and learning
. REM sleep typically occurs 90 minutes after falling asleep and is essential for overall sleep quality and cognitive function
. It is part of the sleep-wake cycle, alternating with non-REM sleep throughout the night
. Most adults need about two hours of REM sleep each night
