It's estimated 22 million Americans suffer from sleep apnea. They actually stop breathing while sleeping, and it causes them to wake up several times an hour. It causes people to be tired during the day, though they actually spent plenty of time in bed. Dr. Thomas Kelly with BMC's Sleep Disorders Center explains what happens: “And obstructive sleep apnea is a condition that creates a situation of fragmented sleep. they may be in bed ten hours but because they have episodes where they can't breathe or their mind keeps waking up, they're waking up 30,40, 50 times an hour. It’s not restorative sleeps and leaves them feeling tired during the day. Left untreated, sleep apnea can lead to depression, heart disease, diabetes and even fatal car crashes.