Bill Clinton, Leonardo Da Vinci, and Albert Einstein are among the notable historical figures to weave sleeping less than five hours a night into their personal mythologies. Odds are you know someone who makes similar claims. The odds are even greater they have no idea what they're talking about.

In an interview in today's Wall Street Journal, former American Academy of Sleep Medicine president Daniel J. Buysse says only five percent of the people who claim to be "short sleepers" (read: people who can legitimately function on limited amounts of sleep) actually are. The other 95 percent "end up chronically sleep deprived, part of the one-third of U.S. adults who get less than the recommended seven hours of sleep per night."

Plus, there's no way to train yourself to be more like a Clinton, Da Vinci, or anyone else in the nighttime overclass the Journal calls "the Sleepless Elite." Geneticists say the short sleeping trait is caused by a genetic mutation, not practice and Red Bull. Scientists at the University of California-San Francisco first discovered the mutation responsible for short sleepers two years ago. At the time, the New York Times called the finding a "major breakthrough in sleep science" that "could unlock answers about insomnia and other sleep problems." Based on the Journal article, it's unclear how much progress has been made. The enduring lesson seems to be: get your eight hours. Unless you're a genetic mutant.