You're groggy, dizzy even. You can't see straight and you sure as hell can't keep your eyes (or your mind) focused on the screen in front of you. And you're pretty sure your boss has noticed. You want to assure her that you're not drunk and you got enough sleep. In fact, you got more than enough. Could that be the problem?  

The Rumor: Sleeping too much is just as bad as not sleeping enough

We've all heard how important it is to get enough rest, even though most of us don't. Everything from obesity to cardiovascular disease to a weakened immune system have been attributed to a lack of sleep. The average person spends about 33 percent of his or her life sleeping. So how much is too much? What if you just slept 2 percent more? What about 7 percent? Can oversleeping be as bad for our health as sleep deprivation? And if it is, why?

The Verdict: Oversleeping can hurt your health

According to WebMD, the amount of sleep a person needs “depends on your age and activity level as well as your general health and lifestyle habits.” Even though the average recommended amount of sleep is seven to nine hours, certain times in your life call for more. According to Russell Sanna, executive director of the Harvard Medical School Division of Sleep Medicine, people need more sleep than usual when they're recovering from illness, major surgery or a radical time-zone change.

However, just because you can sleep for 12 hours on a daily basis doesn’t mean you should. According to Dr. Lisa Shives, director of Northshore Sleep Medicine in Evanston, Illinois, grogginess from oversleeping is known as "sleep drunkenness." Occasional oversleeping doesn’t pose serious health risks, but if you’re consistently sleeping too much and waking up groggy, you may want to consult a physician.

Prolonged daytime sleepiness or nighttime sleep is associated with a disorder known as hypersomnia. Instead of simply feeling tired, those with hypersomnia nap repeatedly throughout the day, usually at inappropriate times (such as at work or even in mid-conversation). Hypersomniacs don’t feel refreshed after they sleep, and often wake up feeling disoriented. Symptoms include anxiety, restlessness, loss of appetite and memory problems, as well as dysfunction in social settings. What causes it? Per WebMD, studies show it can be the result of  “another sleep disorder… dysfunction of the autonomic nervous system... drug or alcohol abuse... [or] injury to the central nervous system.” It can also be caused by certain medications -- or medicine withdrawal.

Oversleeping has been associated with thyroid disease, kidney and liver disease, depression and dementia. But don't think you can catch a few winks and assume your health isn't at risk because you were up before noon. People who get too much and too little sleep have a higher mortality rate. So don't stay up late and set an alarm, OK?