The secret of success: Needing less sleep? by Laura Vanderkam @FortuneMagazine March 20, 2012, 2:53 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Stories abound of business leaders who don’t sleep much. Martha Stewart has claimed to sleep about four hours a night, as has Indra Nooyi, the CEO of PepsiCo PEP . Her predecessor, Steve Reinemund, has gotten up around 5 a.m. to run 4 miles most mornings of his life after going to bed around 11. “I sleep normally between five, six hours,” he said in an interview. “I’ve never gotten more.” But it seems to be enough: “Most of the time I don’t wake up with an alarm.”Is not needing much sleep a secret to success — giving people a chance to work long hours and still have a life?Well, maybe. According to David Volpi, a sleep specialist and founder of Eos Sleep (formerly the Manhattan Snoring and Sleep Center), adults generally need six to eight hours a night. That means that some people, like Reinemund (now dean at the Wake Forest University Schools of Business), can do fine on just six hours. “If you get six hours a night and feel well-rested when you wake up and don’t get tired throughout the day, that kind of tells you,” he says. “Your body will tell you if you don’t get enough sleep.”The good news? If you do need eight hours, plenty of people have found ways to be successful and still sleep almost as much as the average American (who, according to the Bureau of Labor Statistics’ American Time Use Survey, is clocking 8.67 hours of sleep on an average day).MORE: 5 ways to healthier employeesMana Ionescu runs Lightspan Digital, a Chicago-based digital marketing company. As an entrepreneur, she thought she should sleep less and work more. “Somehow people find it heroic to not sleep and brag about it too,” she says. But then “I got behind the wheel after a night without sleep and got into a fender bender.”The accident wasn’t major, “but I wasted many hours of my life as a result.” She’s practiced good sleep hygiene ever since, going to bed at 11 and waking up at 7. “Everything has changed,” she says. “I am able to work more, decisions are easier to make, business is easier to close. I’ve been running half marathons and solved problems that before seemed almost impossible to solve.” In other words, she’s making better use of her hours, even if she’s awake for fewer of them.Jane Glazer, who owns QCI Direct, a multi-title catalog firm with 100 employees, is usually in bed by 10:30 pm and up around 6:30 am. While there’s always the temptation to answer one more email before bed, “you can’t function and lead a company being sleep deprived,” she says. “In the early years of my business, I did try to get by with less, but I quickly learned I would burn out by mid-afternoon.”As for people who claim they only need four hours? “With the billions of people in the world, there are, I’m sure, people that only need four hours of sleep,” Volpi says. “But that would be the exception to the rule.”It’s unlikely that these freaks of nature have all congregated on Wall Street and in the executive ranks of Fortune 500 companies. “I think it’s just macho,” he says. Or whatever the female version of macho is.MORE: 6 questions to ask a job interviewerAccording to the 2007 National Sleep Foundation poll, which focused on women’s sleep habits, mothers who work full-time and have school aged children claim to spend less than six hours in bed per weeknight. But according to the American Time Use Survey, which relies on time logs rather than memories of typical nights, such women slept an average of around eight hours per night when you include weekends (which means that, unless women sleep 13 hours a night on weekends, they’re sleeping more than six on weeknights too).You can chalk the disconnect up to a competitive culture, says Cali Williams Yost, owner of Work + Life Fit, Inc., which consults with companies on organizational issues. “Like taking all of your vacation, for some reason, wanting and getting sleep symbolizes a less than 100% commitment not only to your job but your family,” she says.“Assuming there are some people who truly don’t need sleep, I think everyone else who boasts about how little shut eye they require either has convinced themselves it doesn’t matter … or they have untreated sleep disorders and they’ve reframed not being able to fall asleep or stay asleep as normal when, in fact, they could sleep if they got help.” Then they might enjoy the rest of their 16 to 18 hours per day a bit more.