Can exercise be a bad thing? Sudden death during or soon after strenuous
exertion on the squash court or on the army training grounds, is not unheard of.
{{U}} {{U}} 1 {{/U}} {{/U}}trained marathon runners are not
immune to fatal heart attacks. But no one knows just {{U}} {{U}} 2
{{/U}} {{/U}}common these sudden deaths linked to exercise are. The
registration and investigation of such {{U}} {{U}} 3 {{/U}}
{{/U}}is very patchy; only a national survey could determine the true {{U}}
{{U}} 4 {{/U}} {{/U}}of sudden deaths in sports. But the climate of
medical opinion is shifting in {{U}} {{U}} 5 {{/U}} {{/U}}of
exercise, for the person recovering from a heart attack as {{U}} {{U}}
6 {{/U}} {{/U}}as the average lazy individual. Training can help the
victim of a heart attack by lowering the {{U}} {{U}} 7 {{/U}}
{{/U}}of oxygen the heart needs at any given level of work {{U}} {{U}}
8 {{/U}} {{/U}}the patient can do more before reaching the point where
chest pains indicate a heart starved of oxygen. The question is, should
middle-aged people, {{U}} {{U}} 9 {{/U}} {{/U}}particular, be
screened for signs of heart disease before {{U}} {{U}} 10
{{/U}} {{/U}}vigorous exercise? Most cases of sudden death in
sport are caused by lethal arrhythmias in the beating of the heart, often in
people {{U}} {{U}} 11 {{/U}} {{/U}}undiagnosed coronary heart
disease. In North America {{U}} {{U}} 12 {{/U}} {{/U}}over 35 is
advised to have a physical check-up and even an exercise electrocardiogram. The
British, on the whole, think all this testing is unnecessary. Not many people
die from exercise, {{U}} {{U}} 13 {{/U}} {{/U}}, and ECGs (心电图)
are notoriously inaccurate. However, two medical cardiologists at the Victoria
Infirmary in Glasgow, advocate screening by exercise ECG for people over 40, or
younger people {{U}} {{U}} 14 {{/U}} {{/U}}at risk of developing
coronary heart disease. Individuals showing a particular abnormality in their
ECGs {{U}} {{U}} 15 {{/U}} {{/U}}, they say, a 10 to 20 times
greater risk of subsequently developing signs of coronary heart disease, or of
sudden death.