When it comes to sleep, there is "a perpetual divide between what's known to scientists and what most people do," physician and author James Hamblin writes in The Atlantic.
Not getting enough sleep has been linked to everything from car accidents to depression. But many people still don't understand the importance of sleep. "Sleep experts often liken sleep-deprived people to drunk drivers," Hamblin writes. "They don't get behind the wheel thinking they're probably going to kill someone."
Hamblin wants to set the record straight so people understand the risks of not getting enough sleep—and how to maximize the benefits of the rest they do get—by answering six key sleep-related questions.
1. How much sleep do you actually need?
To best answer this question, Hamblin suggests turning to organizations that have done systematic reviews of the best available evidence, such as the American Academy of Sleep Medicine and the Sleep Research Society. Those groups convened a panel of experts to look at how the number of hours that an individual sleeps is related to the risk for a range of diseases and cognitive effects.
The groups found that most adults should sleep between seven and nine hours per night. Getting fewer than seven hours of shut-eye can leave you impaired, with the effects varying by person, while consistently getting fewer than six can put your health at risk.
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2. Can you train yourself to need less sleep?
It's not likely. While some individuals seem to be biologically equipped to function on much less sleep, there isn't good evidence that "training" can help people reduce their overall requirement for rest, Hamblin writes.
In the 1960s, the U.S. military ran a series of tests to see if soldiers could be trained to function on less sleep. Early results were promising, but lab tests showed that with each night of sleep deprivation, soldiers performed worse on cognitive tests.
David Dinges, the chief of the division of sleep and chronobiology at the University of Pennsylvania, said of the soldiers, "They would insist that they were fine, but weren't performing well at all, and the discrepancy was extreme."
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3. Can caffeine replace your need for sleep?
Hamblin writes that caffeine does a lot of things—but replacing sleep isn't one of them. By interfering with certain neurotransmitters, "caffeine cuts the brake lines of the brain's alertness system," Hamblin writes. "Eventually, if we don't allow our body to relax, the buzz turns to anxiety."
Over the long term, stimulation from caffeine can disrupt your regular sleep-wake cycle. "At that point, many people go in search of products to help them sleep," Hamblin cautions.
And while some studies have found that caffeine is correlated with better health, Hamblin says the science is still unsettled. However, "sleep deprivation is clearly linked to heart disease and strokes," he writes.
In addition, Hamblin warns that energy drinks containing caffeine "have been implicated in thousands of [emergency department] visits in recent years." Sleep is a much more evidence-based way to feel rested regularly and to stay healthy, Hamblin says.
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4. Is your cell phone keeping you awake?
Hamblin says yes: Artificial nighttime lighting can have a negative effect on sleep, as light plays a key role in regulating the body's sleep-wake cycle. When your retinas begin taking in less natural light in the evening, your hypothalamus tells the body's hormone system to do things like produce melatonin—which promotes sleep. But artificial light can interfere with this process.
"All of this is why we're told to minimize screen time before bed," Hamblin writes.
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5. But can't you just take a melatonin supplement to go to bed?
Many people have a cavalier attitude toward supplements because they don't require a prescription to obtain. But melatonin is a hormone, Hamblin notes, and should be used cautiously.
And the evidence for melatonin isn't particularly strong. He says. "Melatonin supplements have been shown to make some people fall asleep more quickly," Hamblin writes. "But they aren't proven to increase the total time or quality of sleep."
"What is clear is that supplement overuse can be dangerous," Hamblin says. The better solution is to make sleep a priority and structure your life so you can get the sleep you need (Hamblin, The Atlantic, January/February 2017).
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