Undercover Investigation

The night owl burns the midnight oil. The lark is yawning at 9:30 p.m. These aren't just stereotypes -- they are real scenarios. Our internal body clock sets our natural sleep schedule.

"Every person's body clock does seem to have a natural setting," says Meir Kryger, MD, director of the Sleep Disorders Centre at St. Boniface Hospital Research Centre at the University of Manitoba.

"You can try to change it," he tells WebMD. "But you can't really fight your biology."

We also have a 'sleep number' -- the number of optimal hours of sleep we need nightly, he explains. "People often boast about getting by on four, five, or six hours of sleep. Donald Trump says he gets by on four hours a night. That's what they want you to believe."

But the truth is most adults need about seven to eight hours of sleep every day to function optimally. When they scrimp on sleep, that number goes up -- at least, temporarily. Few people can adapt to getting less sleep than they need.

And, by and large, Americans are scrimping. In this year's annual Sleep in America Poll, researchers at the National Sleep Foundation divided American adults into five distinct sleep profiles based on their sleeping habits. More than half (52%) fell into the "not so good" sleeper profiles.

Owl-like tendencies often start during teen years, Kryger explains. "Kids tend to go to bed late, get up late, and for some people that continues into adulthood. Some owls seem to naturally switch back and become 'more normal' as they get older. For the others, it can become a big problem: The body isn't ready for bed until 2 a.m., but the job starts at 8 a.m."

In fact, many self-proclaimed owls are really larks, Kryger adds. "If you listen to an iPod in bed or are doing email until 2 a.m., you're not necessarily a night owl. These activities stimulate your system so you don't get sleepy until later. Your natural cycle may be more like a lark."

What's Your Sleep Style?

Healthy, Lively Larks. You're the sleeper that insomniacs envy -- you just don't have sleep problems. You're likely in your 40s, in good health, and consider yourself to be a morning person -- you fall asleep quickly, and are up early. You rarely crave a nap, because you usually get the sleep you need.

Sleep Savvy Seniors. The over-65 set gets the most sleep of any -- about seven hours a night. You take a nap once in awhile (lucky!), and rarely feel tired. Most of you are retired, freed from the pressures of the working world.

Dragging Duos. You're a workaholic -- dragging yourself out of bed early, driving to work drowsy, bringing work home with you. You fall asleep when your head hits the pillow but rarely get enough sleep to function optimally -- playing catch-up on weekends. You may have a partner and one of you probably snores disrupting sleep for both of you. Your relationship may be suffering because of your sleepiness.