No matter how early she went to bed, Maggie couldn’t fall asleep until the early hours of the morning. Though constantly exhausted, Maggie (she asked that I not use her last name) got good grades in high school, but she'd frequently get in trouble for coming in late and napping during her morning classes.

Maggie dreamt of going to medical school. Unfortunately, she couldn't concentrate during early morning science classes in college, and she had to switch her major from biology to literature. Her post-grad situation was no better: Waking up for her 8:30 a.m. teaching position turned her into a zombie, and she lost her job because she lacked enthusiasm. She switched career paths to take on a marketing position that was supposed to be afternoon-only, but once her boss started requiring her to come in mornings, it didn't work out—and she's now unemployed.

Maggie isn't lazy; she suffers from delayed sleep phase syndrome (DSPS)—a disorder that affects one in 750 adults that causes them to be somewhat nocturnal. By that estimate, DSPS affects over 400,000 Americans. Essentially, DSPS means a person's internal clock is set differently. These clocks, called circadian rhythms, are innate and often change over the course of a person’s life—which is why little kids wake up so early, and teenagers prefer to sleep in.

DSPS sufferers have internal clocks that run at least two hours slower than normal, giving them "social jet lag" which is pretty much what it sounds like: They’re out of sync with the rest of society. They struggle to keep their eyes open during morning business meetings because their bodies are convinced it's the middle of the night. DSPS can wreak havoc on their health and careers, causing depression, anxiety, brain damage, heart disease, drug addiction, and a myriad of other afflictions due to sleep deprivation.

DSPS is often confused with insomnia, perhaps because sufferers seem sluggish and tired during the day. But the two disorders are actually very different: Insomniacs have trouble with the actual process of falling asleep, often due to anxiety or other factors. People with DSPS sleep perfectly fine during the hours their bodies tell them to. And DSPS isn't simply the preference to be a “night owl”—DSPS sufferers can’t fall asleep early even if they want to.

All of this amounts to bad news for DSPS sufferers in the world of work. According Cary Cooper, a psychologist and professor at Lancaster University Management School, when people who have DSPS wake up early for work, they become sleep deprived which causes them to be less efficient, innovative, and creative at the office. People with DSPS have trouble finding positions that allow them to work hours that let them get enough sleep. This also results in more stress, and can cause workplace accidents. A 2010 Journal of Occupational and Environmental Medicine study found that sleep deprivation costs companies an average of $2000 a year per worker.

“The evidence is clear,” Cooper says. “We’re losing quite a lot of talent.”

Of course, humans didn't always work 9-to-5 or sleep eight recommended hours at night. Anthropologist Carol Worthman describes the sleep patterns of hunter-gather societies as having huge variations across different tribes and cultures. While for some tribes, sleeping at the same time was a social activity, other tribes slept whenever they could or felt like it. A good deal of research suggests humans aren’t made to sleep eight-hour stretches. The 9-to-5 workday started as a movement in the 1830s. Laws were passed over the next few decades, with Congress passing the eight-hour workday for federal employees in 1876. The 40-hour workweek became part of the New Deal, which is when it became more or less standardized.

DSPS sufferers are perhaps a small population that's benefitting greatly from the growth of flexible work in our economy. Peter Mansbach, a software engineer with degrees from Harvard and Brandeis University, worked in robotics at the National Institute of Standards and Technology. But his body wouldn't align with his workday schedule; his 8 a.m. start time made him sick. He ended up losing his job, so he switched into computer programming—where he found contract work with flexible hours. Unfortunately, being a contract worker meant not getting promoted or having the job stability of someone who could be in the office.

Mansbach has since founded the Circadian Sleep Disorders Network, a volunteer-run support and advocacy group for people with internal clock disorders. "Most people with [DSPS] don’t know about it," Mansbach says. "I get emails from people who say, 'I just discovered your site. I've always doubted myself; people called me lazy. It's great to know there's a real problem here.'"

Though he’s tried many treatments, such as light therapy and melatonin supplements, Mansbach, like most people with DSPS, never found a cure.

"It's easier to treat someone with straight-up insomnia," said Michael Breus, a clinical psychologist at The American Academy of Sleep Medicine. "Nothing works particularly well except getting a night job." Furthermore, if night owls and DSPS sufferers force themselves to live by the dawn to dusk schedule, they deprive themselves of their most productive hours.

"I think no matter what you did to me, I'd never be happy in the morning," said author Michael Lewis, who wrote the bestselling books Flash Boys and Liar's Poker. "And I'd never be sad late at night."

Lewis wrote his first book entirely after midnight, and he continues to write at night. "I can’t get the best stuff out of me any other way," Lewis said. "I used to write until five in the morning. I think my books would be better if I could still do that."

Like many night owl parents, Lewis wakes up early to get his kids ready for school. (Ironically, mounting evidence shows that teens typically have later biological sleep schedules, and as many as 15 percent develop temporary DSPS.) "Morning people ignore the bigotry at the heart of our culture," Lewis said. "It's like a conspiracy of farmers. I'm handicapped by what farmers used to do."

DSPS and work-related sleep deprivation would be unfortunate but unavoidable if our society had to choose one timetable for everyone to live by. Fortunately, that's not the case. Cooper notes that the U.S. has migrated from being a manufacturing-based economy to being a knowledge and service based economy—but our jobs haven’t evolved with this shift. “Come in early. Stay late. That’s always been the American way,” says Cooper. “Managers like to see bodies in the office.”

Flexible work schedules are already very common in Europe. A 2009 study by the European Commission found that flexible working hours is "relatively widespread." Workers with access to flexible schedules in the EU ranged from about 62 percent in Denmark to about 7-to-10 percent in Bulgaria—with most EU countries in the range of 20-to-40 percent. According to Cooper, most U.K. employees will be working half from home in five years.

Traditionally, managers tend to think more people in the office equals more output, but new research shows that people who work flexible hours are more productive and more likely to stay with their company because they are happier and healthier. Thanks to these findings, the U.K. passed a law in June giving every worker the right to apply for a flexible work arrangement.

This is great news; not just for DSPS sufferers, but for their companies. Employers willing to let their employees work flexible hours would enjoy access to a greater number of quality employees, higher productivity, and lower office space costs. In Cooper’s words: “They’d save a hell of a lot of money.”