When fit people get heart attacks

SCUBA diving instructor Carlson Victor Lee was the picture of physical strength, able to swim against an oncoming current when other divers would be sheltering behind a rock. He also owned a dive shop in Batam View Hotel where he conducted diving trips. On August 10, 2002, he died during a dive, triggered by a heart attack.

Running guru James Fixx was the author of The Complete Book of Running, that helped popularise jogging in America. He died of a heart attack while jogging on July 20, 1984.

When you read of these and other reports of sports individuals who suffered a heart attack or sudden cardiac death while playing tennis, diving or running, you may get the impression that vigorous exercise is dangerous to the heart.

Is that so?

A heart attack occurs when blood flow to the heart is critically reduced or completely blocked, causing chest pain. If not treated promptly, the affected heart tissue dies. Before an attack, most victims experience angina (chest pain) that is provoked by blockage of blood flow to the heart. With angina, blood flow is quickly restored, the pain recedes within minutes, and the heart is not permanently damaged.

However, a third of all heart attacks occur without warning signs. The victims suffer from sporadic interruptions of blood flow to the heart that, for unknown reasons, are pain-free, although they gradually damage the heart tissue. The heart is therefore already damaged even though the individual appears fit and strong.

But during vigorous exercise such as jogging, the person who already has a damaged heart or an underlying heart disease, is more likely to die than if he or she were walking or resting. In exercise, the heart may develop an irregular beat, blood pressure can rise to a dangerous level or plaque from a partly-clogged artery can break off and stop blood flow. The arteries supply blood to the heart muscles, bringing to them oxygen and nutrients.

In the case of scuba diver Carlson Victor Lee, autopsy indicated that the front part of his heart was paler than the rest of the organ, indicating the blood supply had been cut off, consistent with a heart attack. Fat was found in the coronary vessels and it was also clogged all around the heart. There was significant thickening on the ventricles, an indication of a heart that had been made to work harder and harder due to increasing resistance in the coronary vessels.

As for James Fixx, he had a family history of heart disease; his father suffered a heart attack at 35 and died of one at 42. He himself experienced cardiac symptoms in the weeks before his death, symptoms of one or more smaller heart attacks that he ignored.

Fixx took up running in 1967 at 35 years old. He weighed 214 pounds and smoked two packs of cigarettes a day. Ten years later, he was 60 pounds lighter and smoke-free. In his books and on television talk shows, he tells how physical exercise had considerably increased the average human being's life expectancy.

Fixx died at 52 of a massive heart attack, during his daily run, in Hardwick, Vermont. The autopsy revealed that cholesterol had blocked one coronary artery 95 percent, a second 85 percent, and a third 50 percent.

Some critics said his death was proof that running was harmful. But given his family history and his unhealthy lifestyle until he took up running, others argued that running has indeed added many years to his life.

The heart is a muscle, and like any other muscle, exercise conditions it to be stronger. A well-conditioned heart pumps in 50 beats per minute the same amount of blood that the heart of a sedentary person would pump in 75 beats per minute. In addition, during rest, a well-conditioned heartbeat is slower. This means the heart does not have to work as hard to get the job done, so the heart rate slows down.

The underlying causes of most heart attacks are high blood cholesterol level, high blood pressure, obesity, diabetes and undue stress. Regular physical exercise counters every one of these risk factors. Exercise also raises blood levels of HDL cholesterol, which helps to cleanse the arteries of deposits.

The main risk factors that exercise cannot change are family history and age. These two factors can serve as a warning. So, if you have family members who have heart attacks before age 65, or if you are middle-aged or older and have been sedentary for years, you should go through a physical checkup before taking up running and other vigorous physical activity.

– Francis Chin, September 2006

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Fit and running, picture from Runners World