Which of the following is NOT a stage of NREM sleep?

In understanding the stages of sleep, it's essential to know that Non-Rapid Eye Movement (NREM) sleep consists of stages that help the body and brain recover and rejuvenate. The first three stages of NREM sleep are recognized: Stage 1 is a light sleep, Stage 2 is a deeper sleep, and Stages 3 and 4 represent deeper NREM sleep with Stage 4 being the deepest state of sleep.

REM (Rapid Eye Movement) sleep, however, is a distinct phase characterized by rapid movement of the eyes, increased brain activity, and vivid dreaming. It is not classified as a stage of NREM sleep; rather, it alternates with the NREM stages in the sleep cycle, typically occurring after a period of NREM sleep.

Understanding this structure is crucial for recognizing how sleep cycles contribute to overall health and the importance of both NREM and REM stages for rest and recovery.