9781422273890

Major cities such as New York are usually lit up twenty-four hours a day.

What Is the Sleep Cycle? The circadian rhythm is not the only cycle that impacts our sleep. Although we may assume that not much happens while we are sleeping, there is in fact a whole lot going on. And all that activity is, yes, cyclical. There’s a popular meme online that goes, “I love sleep because it’s a time machine to breakfast.” The implication is that sleep is a sort of non -experience in which you essentially leap immediately from night to morning. Although the joke is a modern one, that idea—of sleep as an empty phase—is actually a perfect reflection of how people viewed sleep for a long time.

Understanding Sleep

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