Some people claim they don't need seven hours of sleep.
What's normal for Elena Angeli is abnormal for most people.
"If I sleep less than four and a half, I am definitely tired during the day. If I sleep more than seven and a half, I am tired. So there is a sweet spot in there between five and six," she says.
The 35-year-old says she gets about five and a half hours of sleep each night and she never needs coffee or a nap.
While lots of people think they can get by on just a few hours of sleep, researchers say only one percent of the population are true "short sleepers", meaning they don't need the recommended seven to nine hours of sleep each night.
They're a combination of early bird and night owl and they never feel exhausted during the day.
"We're really beginning to just understand the true short sleeper, not the overworking individual who just pushes too hard and plugs through, but the true short sleeper really wakes up feeling fine," says sleep specialist Dr. Helene Emsellem.
Dr. Emsellem, medical director for the Center for Sleep and Wake Disorders in Chevy Chase, Maryland says researchers have found a genetic link between people who function on such little sleep.
Most short sleepers tend to be thin with faster metabolisms.
They have a higher tolerance from pain and are usually of European descent, but most interestingly, they don't develop any of the health issues associated with lack of sleep.
Studies show that not getting enough shut-eye can affect everything from your risk of heart disease and chronic diseases like diabetes to weight gain.
Emsellem says the best way to make sure you're getting the rest you need, is to keep a sleep journal.
Keep notes on things like whether or not you feel refreshed in the morning and how you're feeling late in the afternoon.
Researchers are still studying this phenomenon.
They say they've looked at thousands of people who thought they were natural short sleepers, but only 50 people actually fit the criteria.