In February, a pop-up science column, Annals of Inquiry, is appearing in place of Kyle Chayka’s column, Infinite Scroll. Chayka will return in March.

When Joanne Osmond was growing up, in rural Pennsylvania, her family had two nighttime rules: you had to stay in your room, and you had to be quiet. There was no rule that you had to be asleep—which was fortunate, because Osmond, her three brothers, and her two sisters rarely were. Osmond stayed up late reading novels from her school library. Her sisters loved solving crossword puzzles. Even her father, an engineer, tinkered with television sets late at night and early in the morning. Only Osmond’s mother, for whom the rules had been created, routinely got what she considered a full night’s sleep.

Osmond, her siblings, and her father were what scientists call natural short sleepers. Some people don’t sleep enough because they have insomnia, or work a night shift; they tend to struggle with exhaustion, cognitive impairment, and even long-term health issues, such as elevated rates of depression and a higher risk of heart attack. But short sleepers, who make up less than one per cent of the population, spend significantly less time snoozing without any apparent health consequences. “Growing up, we didn’t realize that there was anything different about us,” Osmond told me. Only in 2011 did she learn that she has a genetic variation linked to short sleep. Her sisters, who were tested in 2019, have variations in the same gene. Osmond, now seventy-seven, sleeps no more than four hours a night.

My curiosity about short sleepers was piqued after several of my friends (not for the first time) made New Year’s resolutions to sleep better. Sleep was also on my mind. I have never had insomnia, but in my late teens and twenties I bartended while going to school, and sleep felt like a luxury that I could opt out of if needed. When I became a journalist, a cup of strong black tea helped me start writing at four-thirty or 5 A.M.—my most productive time—before spending a full day at the office. As I enter my mid-thirties, however, I often start writing after sunrise, and caffeine has lost its power to reinvigorate me. When I’m sleep-deprived, my mind feels like hard leather: unpliant, easily creased under stress.

If you’ve ever wondered what you could do with a few more hours in the day, Osmond suggests an answer. A rough calculation suggests that she has been conscious for thirteen years longer than her average peer from elementary school. She has certainly made use of the time: she went to college for engineering, married an engineer, had five children, in the suburbs of Chicago, and worked demanding jobs in technology and management. While her husband was asleep, she studied educational policy, eventually becoming president of the Illinois Association of School Boards. During one of our conversations, she told me that, after I went to bed, she’d be teaching students from around the globe how to start their own businesses. “The world seems to need eight hours, and I don’t,” she told me. I felt a warm stirring of envy in my gut.

Ying-Hui Fu, a human geneticist at U.C.S.F. who has studied about a hundred short sleepers, told me that they raise fascinating questions about the nature of sleep. She is sometimes asked why short sleepers are so rare: wouldn’t evolution reward individuals who spend less of their lives unconscious? But she speculates that such a trait only became prized in modern times. “Before electricity, there was no advantage to being a short sleeper in darkness,” she said. Fu’s work also suggests a connection between our sleep needs and the ways we fill our days. Many of the people she’s studied are drawn to demanding jobs and intensive hobbies. They often have a high tolerance for pain. Many don’t need to drink tea or coffee, and they don’t get jet lag. “I call them Homo sapiens 2.0,” Fu joked. Perhaps the deepest mystery is how short sleepers thrive on so little rest—and whether anyone else might ever be able to do the same.

Most animals need sleep, but it’s difficult to say exactly why. One leading theory is that sleep replenishes energy that’s stored in brain cells. Another postulates that sleep removes waste from the brain. Still another says that sleep allows us to consolidate memories from the preceding day. If sleep’s purpose is elusive, so is the number of hours the job requires. Bats sleep eighteen to twenty hours a day, while wild elephants sleep just two hours a night. In humans, eight hours is dogma—“My body needs eight,” Fu told me—but our actual sleep requirements depend in large part on genetics.

What we know for certain is that terrible things happen when animals stop sleeping entirely. In 1894, a Russian doctor deprived some puppies of food and others of sleep. The sleep-deprived died within days, but the hungry survived. The Guinness Book of Records no longer accepts entries for the longest time a human can stay awake, citing “inherent dangers associated with sleep deprivation.” Most of us have the opposite ambition: we have become so fixated on sleep amount and quality that sleep books spend months on best-seller lists, and the market for trackers such as Oura and Whoop is valued in the billions of dollars. There is even a modern affliction called orthosomnia, described by one scientific article as “the obsessive pursuit of optimal sleep metrics.” Tragically, it may lead to poor sleep.

Sleep is orchestrated by two systems. The first is the so-called biological clock, which runs the body on a roughly twenty-four-hour cycle of sleeping and wakefulness. We all have slightly different circadian rhythms, which explains why some people (larks) get up early and others (night owls) stay up late. The second system is the homeostatic drive for sleep: the longer you are awake, the tireder you get. One’s circadian rhythm and one’s drive for sleep usually work in tandem, but they can fall out of step, Amita Sehgal, a chronobiologist and an investigator at the University of Pennsylvania’s Howard Hughes Medical Institute, told me. When you’re badly sleep-deprived, you want to go to bed no matter what time it is. (Our reactions to sleep deprivation seem to have a genetic basis, too: after thirty-eight hours awake, identical twins, who are born with identical DNA, performed more similarly on tests of reflexes and alertness than nonidentical twins did.)

People with extreme sleep patterns first became a focus of genetic research in the nineties, after a neurologist at the University of Utah, Chris Jones, met a woman who regularly went to sleep in the early evening and woke up in the middle of the night. Her granddaughter had the same sleep patterns, and Jones had a hunch that their habits might be explained by DNA. He got in touch with Louis Ptácek, a neurogeneticist at U.C.S.F., who helped him identify a DNA mutation that seemed to play a role. Fu joined Ptácek’s research team in 1997. “I was very good at finding mutations,” she told me.

In response to the team’s findings—some of the first on how DNA influences sleep—thousands of people reached out. Many had irregular bedtimes and wake times but slept a consistent number of hours per night. An exceedingly small number, Fu said, went to bed very late and woke up very early. Curiously, they didn’t have the complaints that people with insomnia or other sleep disorders often do. In 2009, after studying a mother and a daughter who were both short sleepers, Fu published a paper about a variation in a gene called DEC2, which influences the production of orexin, a hormone associated with wakefulness. (Orexin deficiency is one of the main causes of narcolepsy.) When Fu bred mice with the same mutation, they slept less than other mice.

Since 2009, Fu and her colleagues have published research on six mutations across five genes linked to reduced sleep needs. (A few more genes are being researched, Fu told me.) Osmond and her sisters have variations on a gene that affects receptors for glutamate, an excitatory neurotransmitter with many functions throughout the brain. A different mutation was found in a father and a son in 2019; when Fu’s team introduced it into mice, the animals didn’t show memory deficits that usually appear in sleep-deprived mice.

Sehgal, who has studied sleep in fruit flies, and who was not involved in Fu’s research, was intrigued by the fact that these genes do not seem to be connected by a particular sleep process or brain pathway. “It’s not one specific thing that stands out,” she said. Mehdi Tafti, a neurophysiologist and a geneticist, said that the unsolved mystery of short sleepers reveals our ignorance about how sleep works. When he looked for DEC2 mutations in hundreds of patients with irregular sleep patterns, he couldn’t find any. Fu believes that short sleepers have developed different ways of sleeping efficiently. Sehgal offered a different explanation: maybe their bodies don’t accumulate as much damage while awake.

In theory, the genetic mutations associated with short sleep—and the pathways they seem to affect—could point to targets for drugs that would safely reduce our sleep needs. The discovery that orexin is linked to narcolepsy has sparked new pharmaceutical research, and last year an experimental orexin-blocking medication showed promise for insomnia in a clinical trial. Experimental drugs increasing orexin may also help people with narcolepsy stay awake longer. But it will be more challenging to develop a drug that transforms us into Osmonds. Fu said that, by finding short sleepers and then backtracking to single mutations, she may be missing out on other, more subtle genetic factors. When scientists scoured samples from nearly two hundred thousand people, in the U.K. Biobank, those mutations alone weren’t associated with extreme sleep patterns. And sleep is so important that Fu would want drug developers to proceed with caution. “The worst thing is, you come up with a drug and have horrible side effects,” she said. “You sleep less, but then, five years later, you get Alzheimer’s.”

We fantasize about getting by with less sleep, Tafti said, because the twin goals of sleeping well and sleeping enough are more elusive than they sound. Good sleep hygiene—things like going to bed and waking up at the same time every day—requires us to set boundaries in our work and family responsibilities. It asks us to make choices that are prudent, but not very fun: leaving a party early, cutting back on alcohol, refraining from late-night snacks and screen time. Of course we’d rather take a pill than do all of that. Unfortunately, Tafti said, “we cannot dissolve the need for sleep.” At one time, clinicians hoped that central-nervous-system stimulants such as modafinil could help us sleep less without consequences, but they were wrong. (Like caffeine, wakefulness drugs suppress sleepiness; they don’t eliminate it.) Maybe the next best thing is to find out for yourself how long you need to sleep. One way to do that, according to the experts, is to go on vacation. Sleep only when you’re tired and get up when you feel rested, and you’ll naturally settle close to your actual needs.

A few weeks ago, my alarm startled me awake at 2:46 A.M. I plodded to the kitchen, where I tried to make myself more alert by turning on some lamps. I’d organized a Zoom meeting with Osmond and two other short sleepers, at a time that they were typically awake but I wasn’t. Two of them had even joined the waiting room early.

Brad Johnson, a sixty-nine-year-old in Utah, had grown up in a family of five short sleepers and three normal sleepers. His mutation is associated with a neurotransmitter receptor found throughout the body, including in parts of the brain that are active during REM sleep and wakefulness. It was 1 A.M. where he was, and he was going to sleep soon.

Lynne White, an eighty-three-year-old in California, is the only short sleeper in her family. She has a mutation that, in lab mice, is associated with reduced non-REM sleep and more brain waves found in deep sleep. It was midnight where she was, and she was planning the rest of her evening.

The trio had never met, and they were curious about one another. Johnson asked how many hours the others usually slept. Osmond, in Chicago, was just waking up, having gone to sleep around 11 P.M. “I’ve been known to stay up, Brad, for three days,” White said, laughing.

Johnson used to sleep five hours, but lately he’s been needing about four and a half. He realized that he was a short sleeper at nineteen, during a two-year Mormon mission that had a bedtime of 10:30 P.M. “It was like asking me, ‘Why don’t you just be seven foot five by tomorrow?’ ” he told us. He recalled hiding in closets or bathrooms to read.

“Our brains never stop,” Osmond said. “No matter what we try to do. It just needs to be filled.”

“You just have to do things,” Johnson agreed. He used to worry that his sleep patterns were unhealthy—after all, he kept hearing that he was supposed to be sleeping much more. Learning about his genes has quieted those anxieties. These days, he’s a retired financial executive with eight children; he chairs a two-hundred-member choir and orchestra, volunteers for his church, and reads untold numbers of biographies. He’s also collecting all the talks and presentations that he’s given in the past fifty years.

Being awake so much can be an isolating experience. “There are times when I look outside and there isn’t a light on in any of the houses in my whole subdivision,” Osmond said. Whereas I might be frustrated by running out of time before bed, a short sleeper has to make sure she doesn’t run out of constructive tasks. (“I think one of my brothers died because he could not keep his mind busy and started to drink,” Osmond had told me previously.) Despite all of her volunteering, tutoring, working, parenting, and hobbying, she is always searching for new interests. In 2021, when Iceland’s volcanoes started to erupt for the first time in hundreds of years, she read everything she could find on geology. Then she got bored and moved on.

Johnson’s children are not short sleepers, but he has seventeen grandchildren, and one of them might be. “I’ll get up at five, and she’ll be up shortly thereafter,” he said. He asked Osmond and White about their families. “I think I annoyed my children,” White said. “I was always waking them up.” When her son was in college, he got up early for a job and found her already awake, reading the newspaper. “You know, I’ve never seen you in bed,” he told her.

I was groggy and enjoyed listening to them swap stories, so I chimed in only occasionally. Johnson and White said that they didn’t need to take painkillers after surgeries. White talked about volunteering to fix people’s devices as part of a club of Apple users.

I was still a little envious of short sleepers, but our conversation also served as a blunt reminder of how difficult it is to change one’s relationship to sleep. Johnson could no more make himself sleep through the night than I could get up every day for a 3 A.M. meeting. While they spoke, I thought about how nice it would be to get back into bed, and perhaps even to make up for lost time by sleeping in. There are some pleasures reserved for longer sleepers, I thought.

Had they squeezed more out of life in the time they’d had, I wondered? White said that, when she was younger, she’d needed the extra hours to run three real-estate companies and raise her children. She often organized her days by asking herself, What do I have left to do? Johnson had also felt a paradoxical time crunch. “I like to say that God knew I needed an extra three hours to keep up,” he said.

But all three said that, in retirement, their experience of time has evolved. White now finds herself asking a more expansive question: What am I going to do? “Joanne sort of inspires me,” she said, of Osmond. “She’s so productive.” Osmond brushed her off, pointing out how frequently White volunteers, and I felt relieved that even short sleepers are self-conscious about how they use their time.

I got the feeling that the trio were happy to have found one another. Before we ended the call, White confessed to a bit of envy of her own. “It sounds wonderful to have a family that you can relate to,” she told Johnson and Osmond. “I don’t have anybody.” She turned to me and joked, “I feel like you created a friendship group for me.”

“You can contact me anytime you want,” Osmond chimed in. “More than likely, I'll be awake.” ♦