ABC News' Mara Schiavocampo, Sarah Netter and Mark Abdelmalek report:

Like many Americans, Jenn Schwaner is busy: She works as a court reporter, cooks for her daughter's softball team and fosters babies for the state of Florida.

But unlike most, she does all of this on less than four hours of sleep a night. And she said she's never tired.

"I feel like I'm living my life instead of sleeping it," said Schwaner, 42, of New Port Richey, Fla. "I really do feel like sleeping is a waste of life."

Watch: Short sleepers - awake and alert on only a few hours' rest.

Her father, Pat Pallentino, 69, of Tallahassee, Fla., is the same way. He usually sleeps four hours a night, but he can get by on as little as one hour of sleep a day.

"I'm not Superman, not an X-Man," he said. "I feel like I'm kind of lucky."

Researchers point to a genetic mutation, calling people like Schwaner and Pallentino " short sleepers," technically meaning they can get by on less than six hours of sleep.

In fact, people with strong genetic short sleeper tendencies may only sleep four or five hours a night, waking rested and refreshed.

"We always knew that there were people who were truly short sleepers and it seems to run in families, but now we have an explanation as to who they are and why they don't seem to need much sleep," said Dr. Joanne Getsy, a professor of medicine and medical director of the Drexel Sleep Center in Philadelphia.

Short sleepers often realize their sleep needs are different early in life, even in childhood. In fact, short sleepers often don't feel well after sleeping a full eight hours.

They don't use an alarm clock and rarely yawn, don't need caffeine and don't take naps.

Dr. Ying-Hui Fu, a lead researcher on short sleepers, said doctors had not seen any health issue related to short sleepers. She said it appeared they lived healthy, long lives.

Researchers say natural short sleepers - which, according to Fu, represent less than 1 percent of the population - are not insomniacs or sleep-deprived but instead are proof that not everyone needs seven to nine hours of sleep a night.

Researchers don't fully understand the sleep regulatory mechanisms that allow short sleepers to get by on so little sleep, but experts say that, somehow, short sleepers can get through the five stages of sleep cycle in less time.

"They are very active, they are very optimistic and they are go-getters," said Fu, a professor of human genetics at University of California, San Francisco.