Sleepiness is serious. It contributes to a significant number of driving deaths as well as other accidents each year in the U.S. Take fatigue seriously. Don't drive or do tasks that require close attention if you're feeling drowsy.

Note: This test should only be used as a guideline and is based on the Epworth Sleepiness Scale, developed at the Sleep Disorders Unit at Epworth Hospital in Melbourne, Australia.

Thank you for taking the sleep-deprivation mini-checkup!

One common cause of daily grogginess is obstructive sleep apnea, a condition in which breathing stops for several seconds during sleep. The cut-off in air and oxygen stress the heart, brain and other organs and can continually jolt people awake - a risky, exhausting syndrome.

The only way to be sure if you have obstructive sleep apnea is to be tested by a physician or hospital sleep center. Learn more about sleep apnea.