Verywell Health on MSN

The 4 stages of sleep: What happens during each cycle

Medically reviewed by Sanja Jelic, MD Key Takeaways The sleep cycle has three NREM stages and one REM stage.Deep sleep occurs in stage 3 and is crucial for feeling refreshed.REM sleep helps in ...
Los Angeles Times

Tired All the Time? Your Sleep Cycles (Or Sleep Calculator) Could Be the Key to More Energy

Ever wonder why some mornings you wake up ready to go, and others you feel like a zombie? The difference often comes down to when you wake up during your sleep cycle, and that’s exactly what a sleep ...
CNET

Alternative Sleep Cycles: How to Survive on 3 Hours of Sleep Each Night

Sleeping for 7 to 9 hours at night isn't the only way to catch some z's. Here are four alternative sleep cycles -- and they're pretty obscure. Annie Miller Medical Reviewer Annie Miller is a licensed ...