Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, December 2, 1993 TAG: 9312020044
SECTION: NATIONAL/INTERNATIONAL PAGE: A-10 EDITION: METRO
SOURCE: Associated Press
DATELINE: BOSTON LENGTH: Medium
Out-of-shape people may face 100 times their usual risk of a heart attack if they suddenly rouse themselves to split wood, lug furniture or otherwise work up an unaccustomed sweat.
In fact, a major study suggests, such activity triggers about 4 percent of all heart attacks. That adds up to about 60,000 in the United States annually.
The danger is by far the greatest for those who never exercise, and regular workouts ease the hazard considerably. But even those who exercise five times a week appear to double their risk when they do something strenuous.
The level of exertion, though, is not especially great. The researchers say the equivalent of running up two flights of stairs without a break is enough to touch off a heart attack.
"Heavy exercise can trigger a heart attack. But more importantly, regular exercise can lower the probability," said Dr. Murray Mittleman, principal author of the study.
The study was conducted on 1,228 heart attack survivors at 45 U.S. hospitals. An analysis was made by doctors from Deaconess Hospital in Boston and published in today's New England Journal of Medicine. They found:
Among people who exercise less than once a week, strenuous activity raises the heart attack risk 107 times. For those who exercise once or twice a week, the increase is 19 times higher. The risk goes up nine times for those who exercise three to four times a week and doubles for people who work out five or more times weekly.
The kinds of exercise that are strenuous enough to touch off heart attacks include jogging, tennis, swimming, cross-country skiing, using a push mower, pruning trees, laying bricks and climbing up and down a ladder.
Just how exercise might trigger a heart attack is unclear. Doctors suspect the strain may fracture a fatty buildup of plaque in the lining of a heart artery, leading to a blood clot.
by CNB