Sleep Stages Explained: Your Nightly Journey Through REM and NREM Sleep
What Are the Different Stages of Sleep and Why Do They Matter?
Sleep consists of two main phases—REM (Rapid Eye Movement) and NREM (Non-Rapid Eye Movement) sleep—with NREM further divided into three distinct stages (N1, N2, N3). Each stage serves unique physiological functions, from light transitional sleep in N1 to deep restorative slow-wave sleep in N3, followed by REM sleep crucial for memory consolidation and brain maintenance. The body cycles through all stages approximately 4-6 times per night in 90-minute cycles, with the proportion of each stage changing throughout the night.