The Four Stages of Sleep Explained

Close your eyes at night, and it may feel as if consciousness simply fades and returns in the morning. Inside your brain and body, the journey is much more active. Inside this episode: - How Do We Know A Stage Exists? - The Two Forces That Bring Sleep - N1, The Threshold - N2, Clearly Asleep - N3, Deep Slow-Wave Sleep Sources include the references linked below. Sources and further reading: - [NHLBI, Sleep Phases and Stages](https://www.nhlbi.nih.gov/health/sleep/stages-of-sleep) - [NINDS, Understanding Sleep](https://www.ninds.nih.gov/sites/default/files/2025-05/understanding-sleep.pdf) This episode provides general education about sleep and the body. It is not medical advice, diagnosis, treatment, or an assessment of any listener. Follow Sleep Science Explained for another clear look at what happens after you close your eyes.