Who Is at Risk?

If you sleep alone, you probably won't know you have apnea until symptoms develop, which can take a while. If someone has complained that your snoring sounds like a jackhammer, suspect apnea. Not all snorers have sleep apnea, but more than half of all heavy snorers do.

James Kiley, M.D., director of the National Center on Sleep Disorders Research at the National Institutes of Health, says women usually recognize the problem. "Often it doesn't happen in the reverse," he says, "because women may not snore as intensely as men so their male bed partner doesn't wake up."

Symptoms may be vague and subtle. You may feel tired and sleepy during the day even after a full night's sleep. Before he became a sheriff's deputy, Jim DeCastro was a mechanic and would fall asleep on the cars he was supposed to be fixing, despite getting 12 hours of sleep.

Apneics may wake up with a headache. They feel irritable, experience memory difficulties, and have problems concentrating. Many sufferers report depression, impotence, or loss of sex drive. Marlene Greene, a computer specialist in New York City, was being treated for depression until a sleep lab determined she really had obstructive sleep apnea. Some people are so exhausted, they fall asleep at the wheel. Patients with sleep apnea are three to seven times more likely to have a car crash, says Allan Pack, M.D., director of the Penn Center for Sleep Disorders.

Jim once fell asleep outside the drive-through window at a bank, was suspected of drunk driving, and then couldn't recall how to sign his name.

Collar size counts. Obstructive sleep apnea is most common in middle age and more likely to strike men than women. "In men 30 to 60 years old, it's as common as asthma and diabetes," says Richard Millman, M.D., director of the Sleep Disorders Center at Rhode Island Hospital.

One big risk factor appears to be body fat. Sixty percent of people with sleep apnea are overweight. But specifically, it's not the poundage, but the neck size that counts. Men with a neck circumference of 17 inches or larger (16 inches for women) are more likely to have their airway collapse while sleeping. So is someone with a double chin or a lot of fat at the waist.

Apnea usually worsens with age because the tissues in the throat become floppier and people gain weight. Men are more susceptible because they often have beefier throat tissues and gather fat in their abdomen, neck, and shoulders -- all factors for a narrower airway.

It's unclear whether apnea is caused by obesity, oversized tissues in the throat, a thick neck, basic jaw structure, or a combination, says Rafael Pelayo, M.D., of the Stanford Sleep Clinic. There may be a genetic link as well. Snoring does run in families, and relatives of those affected with apnea tend to be more likely to have apnea and have shallow breathing.

The heart connection. When you stop breathing, your body experiences a fight-or-flight response: adrenaline is released and blood pressure shoots up. After repeated bursts of nighttime high blood pressure, hypertension may persist during the day. With each apneic episode, the heart has to work harder. That's because there's less oxygen flowing to the heart. The worry is that apnea may increase the risk of heart attack, stroke, and heart rhythm disturbances.

Dr. Millman found that men with sleep apnea were more likely to be obese, have high blood pressure and poor blood sugar regulation -- all risks for heart disease -- though not when the researchers controlled for age and weight. Dr. Millman believes sleep apnea doesn't cause heart disease but it may make underlying heart disease worse.

"If someone has severe apnea and coronary artery disease, the stress of apnea could be equivalent to shoveling heavy snow," says Dr. Millman. That's because an apneic's low oxygen levels compound the problem of reduced blood supply to the heart. A non-obese person with apnea who doesn't have heart disease wouldn't have an increased heart disease risk as long as he didn't have high blood pressure.