Apreviously healthy man in his late 40s died of a heart attack during the Turkey Trot on Long Island last year. Then on Memorial Day, another seemingly healthy man in his 50s went out for a run in Brooklyn and died.
When you hear about someone who has suffered a heart attack or sudden cardiac death while jogging, the immediate assumption is likely to be that jogging is dangerous to the heart. But is it?
The answer is somewhat paradoxical. While jogging, a person -- especially someone with underlying heart disease — is more likely to die than if that person were walking or resting at that same moment. During vigorous exercise, the heart can 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.
But — and this is a big but — overall, people who jog, including those with major cardiac risk factors, are less likely to have a heart attack in the long run than if they had not been joggers.
Centuries ago it was commonly thought that the heart was limited to a certain number of beats and that those who used them up too fast would die young. We now know a lot better.
The heart is a muscle, and like any other muscle in the body, exercising it makes it stronger. It does not have to work as hard to get the job done. This is what is meant by conditioning the heart through moderately vigorous physical activity.
Conditioning occurs by exercising at a level that gets your heart rate within a target zone determined by your age (subtract your age from 220, then take 50 percent and 75 percent of that number to determine your zone).
A well-conditioned heart can pump in 50 beats the same amount of blood that the heart of a sedentary person would pump in 75 beats. In addition, during rest, a well-conditioned heartbeat is slower.
Among the major factors that increase a person's chance of developing coronary artery disease, the underlying cause of most heart attacks, are an elevated blood cholesterol level, high blood pressure, obesity, diabetes and undue stress.
The beauty of regular physical exercise is that it 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 exercise cannot change are family history and age. These two factors can serve as a warning.
If you have a family history of premature heart disease (heart attacks in first-degree relatives that occurred before 65), or if you are middle-aged or older and have been fairly sedentary for years, you would be wise to undergo a thorough physical exam before taking up jogging.
My father did not know this in 1967 when he tried jogging for the first time. His father and his father's brother had had heart attacks in their mid-50s. And although my father had always been physically active (brisk walking and swimming were his midlife activities), he had a heart attack about an hour after his first run.
Someone who should have known better, however, was James Fixx, who died of a heart attack while jogging on July 20, 1984. As the author of The Complete Book of Running, Fixx was an international symbol of the jogging revolution. He also had a family history of heart disease; his father died of a heart attack at 43. And he himself had experienced cardiac symptoms in the weeks before his death, symptoms of one or more smaller heart attacks that he ignored.
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