Will Science Ever Give Us a Better Night’s Sleep?
This seemed like a rare opportunity. Distinctive sleep traits can be hard to spot, because of all the ways we can manage or obscure them — for example, by altering our natural sleep rhythms with environmental inputs like lights, LED screens, alarm clocks and caffeine. And this wasn’t a debilitating disorder for which people would necessarily seek treatment. (The woman did so only because she didn’t like waking up when it was “cold, dark and lonely,” Ptacek says.) In 2001, the research group, then at the University of Utah, announced it had found a genetic mutation responsible for the woman and her relatives’ early rising. After their discovery generated headlines, they were contacted by others who believed they had the “morning lark gene.” By giving them detailed questionnaires to identify those whose early rising was innate, rather than environmentally influenced, the researchers happened upon a family with members who woke up early but did not also go to bed early — they averaged only 6.25 hours of sleep per night yet reported feeling fine afterward. Fu and Ptacek, by now at U.C.S.F., found that they shared a genetic mutation that caused their short sleep. The publication of that finding in 2009 inspired others who habitually sleep less than seven hours per night to contact the group, leading to the identification of the two additional mutations reported this fall, which appear to cause other forms of so-called naturally short sleep.
When engineered in mice, those mutations truncated their sleep without any obvious ill effects; in particular, mice engineered with the second mutation performed just as well on memory tests as non-sleep-deprived mice. The naturally short-sleeping people they’ve met, the researchers wrote in Science Translational Medicine, seem especially healthy, too; they are also “optimistic, with high pain threshold.” (The second of the mutations alters a gene that has also been shown to facilitate learning and memory, reduce anxiety and block the detection of pain.) It’s possible, the researchers theorize, that the mutations that cause short sleep are also somehow “compensating for” or rendering people “impervious to” the negative health outcomes typically tied to sleep deficits. If researchers can understand how the mutations alter brain activity, Fu says, “we can help everybody to sleep more efficiently” — possibly by formulating a drug that achieves the same effect. Because a lack of sleep is associated with such a wide range of negative outcomes, a sleep-optimizing drug could transform almost every aspect of human health.
The question remains, though, how to tell whether sleep is being optimized if we don’t fully know its purpose. The “work” of sleep, whatever that is, may be getting done more efficiently in the short-sleepers than in the rest of us. Or they may be compensating for less sleep more effectively. “How do we know if you’ve accomplished the work?” says William J. Schwartz, a neurologist at Dell Medical School at the University of Texas at Austin. “At the moment, still, the routine clinical measure that you’re getting enough sleep is that you’re not sleepy. That’s not going to get us very far.”
But it is a starting point, however crude, for identifying sleep anomalies, and characterizing more of them in finer detail has begun to reveal other potentially heritable traits. Sleep apnea, for instance, was once thought to be a structural problem with a person’s airway; it is now thought to encompass several subtypes, classified by subtly different symptoms throughout the body, some of which might be genetic, says Clete Kushida, medical director of the Stanford University Sleep Medicine Division. “In the next couple of years, there’s going to be more exploration and more findings that will show maybe some of the disorders we thought weren’t genetic might be genetic, and some that we thought were more homogeneous aren’t,” he says.