What Is REM Sleep and Why It Matters (September 2026) Guide

What Is REM Sleep and Why It Matters

REM sleep (rapid eye movement sleep) is the fourth stage of sleep where most of your vivid dreaming takes place. During REM, your brain becomes highly active while your body experiences temporary muscle paralysis, your eyes move rapidly behind closed eyelids, and your heart rate and breathing speed up. This stage makes up roughly 20 … Read more