DEAR DR. DONOHUE: I would like to know what sleep apnea is. Is it true that it makes your heart stop beating? I thought if your heart stopped beating, you’d die. My friend, who has sleep apnea, has to wear a breathing mask when she goes to bed. She says her heart stops beating during sleep. I don’t think she understands this, or maybe I don’t. Please clarify. – B.F.

ANSWER: It’s definitely healthier for your heart to keep beating.

Sleep apnea affects millions of Americans. Their hearts don’t stop beating; they stop breathing. “Apnea” (AP-knee-uh) means “no breath.” Let me expand on this for the many other readers who have asked about it.

People with sleep apnea are usually loud snorers. The loudness of their snoring increases to a crescendo, and then comes sudden silence. The silence marks the apneic (no-breathing) period. Breathing stops for 10 or more seconds. The apneic person grunts, partially wakens and resumes breathing and snoring again. These apneic episodes occur many times throughout the night.

These no-breathing spells cause a drop in blood oxygen, which has a deleterious effect on health. Lack of oxygen promotes high blood pressure, heart disease and stroke. Sleep apnea patients are tired and sleepy during the day, since interruptions of sleep disrupt the refreshment of the brain that comes from a good night’s sleep. Often, they have morning headaches.

No-breathing episodes (and snoring) are the result of redundant tissues at the back of the mouth and upper throat that collapse and block air flow into the lungs.

If people are overweight, weight loss can cure both snoring and apnea. Sleeping on the side keeps the throat opened. Most, however, have to use CPAP – continuous positive airway pressure. It’s a mask that fits over the nose and mouth. The mask is attached to a machine that delivers pressurized air to the patient. Pressurized air forces its way into the lungs.

DEAR DR. DONOHUE: I have been taking vitamin B-12 shots for more than 10 years. I have pernicious anemia. Don’t these shots ever stop? Can’t I take B-12 by mouth? It would make things so much easier for me. – L.P.

ANSWER: Vitamin B-12 assists in the production of red blood cells and keeps nerves healthy. A B-12 deficiency leads to a dearth of red blood cells – anemia. It’s not that you don’t get enough of the vitamin; the trouble lies with your stomach. It stopped making intrinsic factor. Intrinsic factor takes B-12 by the hand and leads it through the digestive tract wall so that it enters the circulation and makes its way to the bone marrow, where blood cells are assembled. Shots of B-12 bypass the need for intrinsic factor.

In North America, pernicious anemia is most often treated with injections of the vitamin. In Europe, the practice is to give people large oral doses of it. Only a small portion of the vitamin is absorbed, but because the dose is so large, it’s enough to restore blood cell production.

If you find the shots inconvenient, ask your doctor if the oral route would be appropriate for you.

DEAR DR. DONOHUE: Who owns medical records, the doctor or the patient? I got into a fuss with my doctor and want to make a change. I asked the doctor’s receptionist if I could have my records. She informed me, in no uncertain terms, that I could not.

I have been with this doctor for a long time, and the record contains all the tests and X-rays I have had through the years. I don’t want to have to start from scratch with a new doctor. What do I do? – K.V.

ANSWER: Laws differ from state to state, but in most places it’s the doctor who owns the medical records.

Patients have a right to request a copy of their records and doctors can charge a “reasonable” fee for making the copy. This is done all the time. Neither the doctor nor the receptionist should squawk. If they do, take the matter to the local medical society.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.