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Why do we have stages of sleep?


This week we have a TPL Kids website visitor who with the extra hour of sleep this weekend, may have spent that extra hour pondering about the stages of sleep.


Sleeping is a cycle that is divided into four stages. Sleeping progresses from one stage to another. For a detailed explanation, we’ve found an article in Harvard Business Review that describes the stages of sleep. Here’s an excerpt from that article:


Healthy sleep is divided into four-stage cycles. As we progress through stages 1 and 2, we become increasingly unplugged from the world until we reach the deep sleep that happens in stage 3. In deep sleep, both brain and body activity drop to their lowest point during the cycle, and blood is redirected from the brain to muscles.

The fourth and final stage is named for the rapid eye movement — REM — that is its defining characteristic. Our brains become busily active in REM sleep, too, even more so than when we are awake. Dreaming happens during this stage. 

So the next time you’re trying to fall asleep, don’t think about the four stage sleep cycle. Just try counting sheep. 


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