Rapid Eye Movement Sleep, often abbreviated as REM sleep, is a unique phase of the sleep cycle characterized by quick movements of the eyes, increased brain activity, and vivid dreaming. This stage typically occurs about 90 minutes after falling asleep and recurs several times throughout the night, with each period getting longer. During REM sleep, the body experiences temporary muscle paralysis, preventing individuals from acting out their dreams. This stage is essential for cognitive functions such as memory consolidation, learning, and emotional regulation, making it a crucial part of a healthy sleep pattern.