Cracking the Genetic Code of People Who Need Less Sleep

Science Uncategorized

Natural short sleepers—who thrive on very little shut-eye—may share a rare gene.

Night owls get a bad rap. In modern culture, any night person—who also naturally needs at least eight hours of sleep to function well the next day—is likely to be looked down on as a slacker who lacks a robust, puritan work ethic.

All too often, someone with a natural sleep-wake cycle that doesn’t conform with post-industrial norms or fit the mainstream work-a-day world, “Rise and Shine!” at dawn priority structure is labeled, judged, and stigmatized for not being “up and at ’em” early enough.

“Nothing good ever happens after midnight!” is a timeless maxim that some say dates back to stories of Solomon warning his son about adultery in the Bible. This adage puts “early-to-bed and early-to-rise” habits on a higher moral ground than being a nighthawk. The saying also reinforces the idea that “good” people go to bed early.

While writing this piece, I wanted some neutral synonyms for “night owl.” Suffice to say, I had a LOL moment when I saw that Thesaurus.com only equates “night owl” with “as in dissolute” or “as in Playboy.” Their laundry list of synonyms for “night owl” all have negative connotations: “Corrupt, debaucherous, degenerate, depraved, evil, fast and loose, lewd, lax, slack, unprincipled, wanton, wayward, and wild.”

Despite the negative associations with being a night owl, there are obviously countless examples of legendary creative greats and prolific writers (e.g., J.R.R. Tolkein, Bob Dylan, Carl Jung) and very successful people who are notorious for doing their best thinking and writing late at night.

However, on the flip side, some people (like myself) can only flourish on a very-early-to-bed, very-early-to rise routine and have trouble staying up past 10 p.m. (seven days a week).

Over the past few weeks, I’ve been thinking a lot about the genetic and familial aspects of sleep-wake cycles. Everyone in my family has a quirky chronobiology. I take after my father and grandfather, who both tended to wake up every morning around 4 a.m. and would usually conk out by 9 p.m., even on weekends.

That said, other members of my family do their best thinking in the wee hours and prefer to work the night shift. For example, my older sister has written a few scholarly books while burning the midnight oil. And my younger sister is a FedEx pilot who captains Boeing 777 airplanes on round-the-world flights that usually depart when everyone else in that time zone is sleeping.

One reason my younger sibling took a job with FedEx is because of her chronobiology; she prefers flying all-night-long and has trouble functioning on a traditional 9-to-5 circadian work cycle. As a female Captain, she breaks stereotypes and is one of the most regimented people I know. She’s also the antithesis of all the ridiculously negative synonyms associated with being a “night owl” listed above.

Technically, as an extreme early bird who naturally dozes off around 8 p.m. and rises in the predawn hours, I’m what sleep experts such as Louis Ptáček and Ying-Hui Fu of the University of California, San Francisco (UCSF) classify as having “advanced sleep phase” or ASP.

Some sleep experts refer to those of us who are genetically wired to fall asleep really early as having ASPD—with the “D” standing for “Disorder.”

However, in a recent Q&A I had with Ptáček, he clarified that his team doesn’t consider ASP a disorder unless the individual dislikes rising before daybreak, misses out on nighttime social activities, and considers being an “extreme morning chronotype” an undesirable trait.

Our Q&A was inspired by another recent study (Curtis et al., 2019) that was also senior co-authored by Ptáček & Fu. This paper was published on August 6 in the journal SLEEP and reported that about one in 300 people has a genetic predisposition for ASP. Statistically, in the scientific world, a 1/300 ratio means that ASP is “not exceedingly rare.”

In my August 21 Q&A with Ptáček, he also pointed out that there appears to be a genetically driven variation in how much sleep each person in the general population needs every night. The two extremes in a continuum are described as “natural short sleepers” (NSS), who generally need less than the typical 8-hours of nightly sleep, and “natural long sleepers” (NLS), who need more sleep than the average person.

The exact reason that having a genetic disposition for NSS may be associated with a wide range of benefits remains a mystery; identifying specific “natural short sleep” genes is just a first step.

“It’s remarkable that we know so little about sleep, given that the average person spends a third of their lives doing it,” Ptáček said in a statement. “This research is an exciting new frontier that allows us to dissect the complexity of circuits in the brain and the different types of neurons that contribute to sleep and wakefulness. Sleep is complicated. We don’t think there’s one gene or one region of the brain that’s telling our bodies to sleep or wake. This is only one of many parts.”

Fu and Ptáček believe that their research on genetic and familial links to ASP, NSS, and NLS represents a crucial step towards better understanding the connection between getting a good night’s sleep and staying healthy. 

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