Whether you're a morning person or a night owl, an article on the New York Times points out that you might be negatively affecting your health when you try to live and work outside of that preference. When you're forced to wake up at a time you're not used to, it messes with all kinds of things.
The New York Times highlights just a few problems:
Sleeping out of sync with your innate preferences can be detrimental to your health, especially for late chronotypes, who tend to be the most at odds with typical work schedules. A study conducted by the National Institutes of Health and published in March in PLOS ONE found that obese adults with late chronotypes tended to eat larger meals, develop more sleep apnea and have higher levels of stress hormones and lower levels of HDL, or "good," cholesterol than obese people with other chronotypes.
Likewise, when you're forced to wake up earlier than your body wants to, you experience a sort of "social jet lag" caused by the mismatch of your schedule and your chronotype. Of course, you can't usually convince your boss to let you sleep in and come in whenever you want, in which case The New York Times recommends getting outside more to get an infusion of sunlight.
Everyday Jet Lag [New York Times]