How much sleep do you need? The answer is (partly) in your DNA
Between the extra hours of darkness, the chilly weather and the holiday feasts, it’s natural to glance over at your alarm clock a little more forlornly than usual this time of year. If there’s ever a time to sneak in a few extra Z’s, this is it. It turns out that just how many of those Z’s you need could link directly to the letters that make up your genetic code.
A set of research papers suggests that some people need less sleep than others based on a few genetic changes. The papers from the neurology team at the University of California, San Francisco (UCSF) identified three genes that researchers can link to needing less sleep. Two of those papers came out in 2019.
While it’s natural to be jealous of people who don’t ever long to sleep through their alarm, there are more important stakes here. Sleep is one of neuroscience’s greatest mysteries. We spend a third of our lives sleeping, but scientists still don’t know precisely why.
So perk up! We’ve got a lot of sleepy science to get through, and you’re not going to want to doze off during this one.
The Perky Genes
The team at UCSF carved a new path in sleep science when they first identified a genetic reason that people might need to sleep less, a change on the DEC2 gene. That groundbreaking paper, published in 2009, kicked off a wave of people contacting the team, all with claims that they too needed less sleep than the average person.
Ten years later, UCSF scientists have linked another pair of genes to sleep duration. To reach the conclusion, the team studied people with specific mutations, then induced those mutations in mice and studied the outcome in the animal models. Through this meticulous process, UCSF linked ADRB1 to the need for rest in an August 2019 article in Neuron. They also associated the neuropeptide S receptor 1 (NPSR1) gene to sleep regulation in an October 2019 article in Science Translational Medicine.
The second paper studied a father-son pair, both of whom had a NPSR1 mutation. The team studied the pair’s sleep patterns and conducted memory tests to see if they lost cognitive function due to getting less sleep, like most people would. Surprisingly, the study found that losing sleep did not have the typical effect on the family members with the NPSR1 mutation.
[Team Lead Ying-Hui Fu, PhD,] would not reveal any more information about them to protect their privacy, except that they are fully rested after four to six hours of sleep instead of the more typical seven to nine. Also, Fu says, the duo and others with similar mutations are more optimistic, more active and better at multitasking than the average person. “They like to keep busy. They don’t sit around wasting time,” she says.
Between the three identified genes, we now have a very strong case that genetics affects sleep duration.
Sleep and Your Genome
Whenever we have even the slightest evidence that a genetic change affects day-to-day function, companies come forward to offer consumer testing for that change. Consumer tests are already offering to look at genes ranging from ones associated with narcolepsy to ones associated with restless leg syndrome, all in hopes of giving you a picture of the kind of sleep your genes will grant you.
As is the case for many consumer tests, the marketing has a tendency to get out in front of the science. While these tests can potentially give interesting insights, it’s still incredibly important that you base your personal habits off best practices, consultation with doctors and what your body is telling you.
An article from UCSF explaining some of their findings warns of what happens if you don’t get the proper amount of sleep:
“Today, most people are chronically sleep deprived. If you need eight to nine hours, but only sleep seven, you’re sleep deprived,” Fu said. “This has well-known, long-term health consequences. You’re more likely to suffer from cardiovascular disease, cancer, dementia, metabolic problems and a weakened immune system.”
That’s part of the reason it’s so important to understand why some people are more efficient sleepers; it’s also a great reason to get as much sleep as your body tells you to get.
The Greater Mystery of Sleep
It’s hard to believe we still don’t know precisely why we sleep, given that we spend a third of our life doing it, but science is full of mysteries. These studies into genes linked to sleep duration could help us uncover some of the secrets of sleepiness.
Scientific American quotes Fu on the potential, referencing the father-son pair with the NPSR1 mutation:
“These people sleep more efficiently,” she says of the father-son pair. “Whatever function sleep is doing for us, it takes us eight [hours to feel rested], but it takes them six or four hours. If we can figure out why they are more efficient, we can use that knowledge to help everybody to be more efficient.”
This science helps build on other research, like a story we covered in this year’s Guidebook on how DNA repairs itself during sleep. Here’s an excerpt from pg. 15:
The small, transparent zebrafish in the study were genetically engineered to have colorful chemical tags on the chromosomes in their neurons. The tags allowed scientists to track the chromosomes using a specialized microscope.
When the fish were awake, scientists observed that the tagged chromosomes moved very little. DNA strands, which break as part of the normal wear-and-tear of life, became damaged and built up in the neurons of the fish. If the researchers kept the fish awake by tapping on the tank, the damaged DNA would build up to the point that the fish were at risk of dying off altogether.
After the fish went to sleep, their chromosomes started to change shape rapidly, allowing for repair at different points along the DNA strand. Introducing a drug into the tank to make the fish sleep during the day led to similar results.
We still have lots to learn about sleep across the animal kingdom. How we can get less of it is only a tiny fraction of what is worth exploring.
Stay Woke, Get Sleep
It’s clear that we’re nowhere near replacing your morning cup of coffee (or my morning mug of tea) with some genetic miracle. Some people just need less sleep than others. So again, listen to your body. Sleep deprivation can have serious consequences, and most of us can’t afford to skip the Z’s. Sleep well, my friends!
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