In a study of 29 sleep apnea sufferers, a U.Va. School of Medicine research team found that they had had seven times more wrecks than a control group of people without apnea and were at fault in accidents eight times more often.

People with sleep apnea suffer from fragmented sleep, lack of deep sleep and oxygen deprivation that make them "pathologically sleepy during the day," said Dr. [Larry J. Findley], an assistant professor of internal medicine.

Once diagnosed, sleep apnea is a highly treatable disorder, he said. Many sufferers find relief after losing weight, and 70 to 80 percent sleep well if they wear a C-PAP -- continuous positive airway pressure -- device, a mask that blows air through the nose and holds the airway open.