Mind & Body

There's a Genetic Mutation That Makes People Need Less Sleep

It's easy to feel like there aren't enough hours in the day, and when you need to sacrifice something, the first thing on the chopping block is usually sleep. For most of us, that makes for an unfocused, moody, miserable day. But it turns out that some people can take a few extra hours to get everything done while avoiding that all-too-familiar fogginess. That's thanks to two rare genetic mutations that allow them to feel rested on less sleep than the rest of us.

The Sky's Awake so I'm Awake

Health experts estimate that we spend about one-third of our life sleeping, and yet the Centers for Disease Control reports that about the same proportion of American adults don't get adequate sleep (they recommend seven hours or more per night). You might think you can get by on little sleep (and you can find out by taking this quiz), but chronic or long-term sleep deprivation tends to lull you into a false sense of security. Studies show that after surviving on little sleep for a long period, people's self-rated sleepiness tends to improve despite the fact that their performance on tasks continues to decrease. Meanwhile, their sleep habits may lead to serious health complications over the long run, including diabetes, heart disease, and high blood pressure.

But a fortunate few are able to sleep six hours or fewer without any ill effects, and in 2009, scientists at the University of California, San Francisco set out to determine how. They studied a family of "short sleepers" — people who only get four to six hours of sleep but wake up bright as a daisy — and determined their superhuman sleeplessness was due to a mutation of a gene called DEC2, which helps manage the body's circadian rhythms.

One of the hormones that DEC2 regulates is orexin, which is involved in maintaining wakefulness. DEC2 functions as a timekeeper, lowering alertness at night by blocking orexin production but easing its grip in the morning so orexin can wake you up and keep you awake throughout the day. The DEC2 mutation in short sleepers reduces their bodies' ability to slow orexin production, causing them to stay awake longer.

Wake Me Up Inside

But it's rare to find any bodily process that's governed by a single gene. If we're going to get a better grasp of sleep, scientists need to find the other genes at play. That's where the team's latest research, published last month in the journal Neuron, comes in.

To find more short-sleep genes, the scientists screened for genetic mutations in people known to be short sleepers and hit upon one particular family with a rare variant in a gene called ADRB1. ADRB1 codes for a receptor for the hormone norepinephrine, which generally controls the body's motion and alertness. Your body pumps out norepinephrine during a "fight or flight" response, snapping your brain to attention and making your heart race. As you might imagine, norepinephrine is usually at its lowest levels during sleep.

The scientists genetically engineered mice to have this same ADRB1 mutation and found that they slept for about an hour less, on average, than non-mutant mice. When they looked at the brainstems of the mutant mice, the scientists saw that cells studded with this receptor were active when the mice were awake but quiet during their deep (non-REM) sleep. Stimulating the neurons carrying ADRB1 also immediately woke the mice from deep sleep. The team suggests that the mutation of ADRB1 makes neurons carrying the gene more active, subsequently causing the organism to be more awake and content on less sleep.

So what if you get by on little sleep? Is it possible you're a mutant? Unfortunately, the chances that you have this sleep gene mutation are vanishingly low; the researchers estimate that it's present in four out of every 100,000 people. Just because you're able to wake up early and keep going after only a few hours of sleep does not mean you're what the researchers consider to be a short sleeper.

"These are not people who've trained themselves to wake up early. They're born this way," Ying-Hui Fu, an author on both studies, said of natural short sleepers' habits in a press release.

Several drugs can already manipulate norepinephrine receptors to treat things like psychiatric conditions, cardiovascular problems, glaucoma, and migraines. Further research on these mutations might add sleep disorders to that list, and may even produce the overachiever's dream: adding more hours to the day by enabling the body to stay awake longer without consequence.

For now, though, you'll need to keep making an effort to get enough shuteye and optimize your environment (like banishing screens and making your room cold) to get the best sleep possible.

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Get a little extra help with your own sleep with "The Sleep Solution: Why Your Sleep is Broken and How to Fix It" by W. Chris Winter, M.D. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Steffie Drucker September 20, 2019

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