We (hopefully) sleep 8 hours a night — that’s nearly a third of our lives! But how much do we actually know about it? Sleep is made up of several stages that cycle throughout the night. This article explains how it works.
Contrary to popular belief, sleep is not a passive state in which the brain shuts down. In fact, it’s quite complex, and the brain can be very active. During sleep, the brain’s fuel supply is replenished.
Our sleep consists of short REM sleep and longer non-REM sleep. REM stands for Rapid Eye Movement — if you watch someone during this phase, you can see their eyes move beneath their eyelids.
Sleep progresses through various stages, repeated 4 to 6 times per night.
First comes light sleep (stages 1 and 2), followed by deep sleep (stages 3 and 4), and finally REM sleep. During REM sleep, the brain is as active as it is when awake. This is the phase in which most dreaming occurs, which helps us process information and maintain memory. During REM sleep, the body’s muscles are temporarily paralyzed to prevent us from physically acting out our dreams.
In general, the quality of sleep is more important than the total number of hours. With just 4 to 5 hours of core sleep, the essential mental and physical recovery already takes place.
Still, sleep deprivation can have negative consequences. It’s believed to contribute to weight gain, mental health issues, and emotional imbalance.
Did you know…
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You die sooner without sleep (around 10 days) than without food (about 2 weeks)?
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Some people take naps with their eyes open and aren’t even aware of it — so you can’t always tell if someone’s awake without medical monitoring?
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Some people can wake themselves up at a specific time without using an alarm clock?
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You can reduce blue light from your phone, TV, and computer with apps — but the mental stimulation from all the content still disrupts sleep?