That goes on for ten, twenty, thirty, sometimes sixty seconds. And the efforts of the chest finally wake the person up briefly, usually without their knowing it. And they breath a few times. Get their oxygen levels back up, and then as they fall back into light sleep, the whole business may happen again. And so that's what sleep apnea is.
DAVID FOLK THOMAS: And, Dr. Zak, this does not sound like it's a very healthy scenario.
SHELLEY ZAK, MD: Not at all. There are very good data that show an association of sleep apnea with high blood pressure, heart attacks and also, probably, stroke. It really is an important medical problem. And the person can go on for a long time not worrying about. Eh, they feel a little sleepy, they're not refreshed in the morning. The reality is this has serious public-health ramifications. And, if nothing else -- let's just forget the heart attack and stroke issue -- you're not refreshed. Because what happens, as Dr. Wagner mentioned, is that one gets into this vicious cycle. Get drowsy, you have this obstruction, and then an arousal. Drowsy, obstruct, arouse. Drowsy, obstruct, arouse. And so the sleep is extremely broken up, unrefreshing, and, if nothing else, the potential for a car accident or anyone who operates heavy machinery, is quite high. And perhaps even at that level, is our greatest sense of problem.
DAVID FOLK THOMAS: And Dr. Wagner, how do you know if you have sleep apnea? I mean, nobody ever snores, right? Because, they don't hear it themselves?