We spend a third of our lives asleep, and it's clear that without it our brains don't function as well, yet little is known about exactly why we do it. Even less understood? Why we don't. As many as 35 million Americans experience chronic insomnia, and yet in 2006 only $20 million was spent on research (Compare that with the $123 million spent on advertising the prescription sleep aid Ambien.)
In the six years that author, professor and lifelong insomniac Gayle Greene spent researching and writing her book "Insomniac" (during which, ironically, she says she got the best sleep of her life), she learned almost all there is to know about sleep and the lack thereof. Here are five common myths about how we get our shut-eye and why:
1. Humans Need Eight Hours Sleep a Night: There are many ways of sleeping and few cultures sleep in eight-hour consolidated blocks like we do. In places like Bali and New Guinea, people tend to slip in and out of sleep as they need it, napping more during the day, and getting up more at night. Until the industrial era, many Western Europeans divided the night into "the first sleep" and the "second sleep." They'd go to bed soon after dark, sleep for four hours then wake for an hour or two during which they'd write, pray, smoke, reflect on dreams they'd had, have sex or even visit neighbors. In fact, there's some evidence to suggest that this sleep pattern may be the one most in tune with our inherent circadian rhythms.
2. Sleep Isn't Just a Bodily Function: Sleep is a biological, physiological system, akin to the cardiovascular system, the nervous system and so on. Like any other system, it is highly variable (some people have weak systems, some people have strong systems), and it wears out and gets more fragile with age.
3. Animals Don't Have Sleep Problems: Insomnia occurs in animals and insects, too, sort of. Technically, insomnia is defined as a "complaint," and since animals can't complain, it's difficult to measure in them. But researchers at Washington University bred "short-sleeping fruit flies" down 90 generations so that they would act like insomniacs. The result? The flies lost their balance and their memory; they could no longer learn.
4. Falling Asleep Is a Gradual Process. Nope. Instead, for most people, it switches on and off like a light switch. But for insomniacs and narcoleptics, the switch doesn't quite work. Instead they inhabit the space in between—never entirely awake, nor entirely asleep.
5. Sleeping Less Burns More Calories. In the short term, yes, but sleeping less probably won't help you lose weight. Lack of sleep suppresses our natural appetite-depressants, while fueling appetite-increasers, often leading to weight gain. It's as if, as Greene says, your system is so depleted, your body is crying starvation.