How many periods of REM sleep does a normal, healthy adult typically experience?

A normal, healthy adult typically experiences 3 to 4 periods of REM sleep throughout a night of sleep. REM, or rapid eye movement, sleep is crucial for various functions including memory consolidation, emotional regulation, and overall cognitive performance. Each cycle of sleep consists of multiple stages, with REM sleep occurring approximately every 90 minutes, leading to several episodes during a typical night. The duration and frequency of REM sleep can depend on factors such as age, sleep patterns, and overall health, but the general range of 3 to 4 episodes in a night is widely accepted in sleep research and clinical practice.