Are There Four or Five Stages of Sleep

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As I was researching material for my previous article, a detailed explanation of the 4 stages of sleep, I was a little confused, as there were some sources referring to 4 stages of sleep, and some referring to 5.

The majority went with 4, so I followed suit. But I couldn’t leave the question unanswered.

Which is Correct? 4 Stages of Sleep or 5 Stages of Sleep?

Key Takeaways

  • The sleep cycle is composed of both non-REM (NREM) and REM stages, which the brain cycles through several times each night.

  • The traditional classification included five stages of sleep, but recent standards combine two of them, resulting in four distinct stages.

The Number Of Stages of Sleep – 4 or 5?

Historically, sleep was divided into five stages, with stages 3 and 4 representing deeper levels of sleep. However, modern classifications by AASM (American Academy of Sleep Medicine) merge these into a single stage, known as N3 or deep sleep.

I am indebted to the published writer for Forbes and Medical Daily Hypnopompic on Quora for clearing up my confusion.

Quality of Sleep Not Number of Stages

While you might hear both numbers, it’s not about the quantity but rather the quality and characteristics of these stages that matter.

Rather than repeat myself, I refer you back to my previous article on the 4 stages of sleep.

But first, just a quick note – which I will cover in more depth tomorrow – to distinguish between …..

Stages of Sleep vs Cycles of Sleep

Each cycle of the stages lasts about 90 to 110 minutes, and we need to complete several of these cycles for a restful night.

More tomorrow!

Author

  • Joy Healey

    Qualified as a nutritionist with The Institute for Optimum Nutrition. A 3 year course in the United Kingdom. Please note, the nutritional qualification is NOT a medical qualification. If you have medical conditions, you should always consult your registered medical practitioner rather than relying on anything you read on my site.

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