Sporadic workouts may be hazardous to your health

November 12, 2000

NEW ORLEANS, Nov. 13 - People who only exercise "every-once-in-a-while" have a small but definite increase in their risk of an exercise-related fatal heart attack or cardiac arrest compared to those who work out more regularly, according to a study reported today at the American Heart Association's Scientific Sessions 2000.

The study was conducted among members of one of the larger chains of American health and fitness centers, its authors suggest the findings may apply to infrequent exercisers and occasional weekend athletes as well.

Previous research has shown that vigorous exercise can precipitate cardiovascular complications, particularly in habitually sedentary people with cardiovascular disease. However, the earlier studies involved relatively small numbers of people. This unique database included 320 fitness facilities and nearly three million members.

During 1997 and 1998, 71 fatal heart attacks or strokes occurred among the club's members and guests during a total of 182.3 million workouts. Almost half the deaths occurred in people who exercised less than once a week.

"Exercise by itself is safe," says Barry A. Franklin, Ph.D., director of cardiac rehabilitation at William Beaumont Hospital in Royal Oak, Mich., and adjunct professor of physiology at Wayne State University School of Medicine in Detroit. "The problem occurs when you have vigorous exercise and a diseased or susceptible heart. Those who die tend to be older, which is not surprising, and tend to be infrequent exercisers. Moreover, these sporadic exercisers often had one or more risk factors for, or a history of, cardiovascular disease."

He compared the situation of people who exercise sporadically to a man "who generally sits on his couch then goes out twice a year to shovel heavy, wet snow after a big storm, and one day keels over dead from a heart attack.

"We don't want to alarm the public," Franklin says. "Although the relative risk may be increased for the occasional athlete, the absolute risk - the chance of a heart attack actually happening - remains very, very low."

He and his colleagues sought to determine the frequency of cardiovascular deaths in fitness clubs nationwide, and the relationship between the frequency of exercise and a fatal heart attack or stroke. Because the fitness club members must use a computerized card to gain admission to their centers, Franklin's team could determine the number and frequency of visits made by members who died during or immediately after a workout.

"We found a very small number of cardiac events, when you consider the total number of workouts," says Franklin, "The fatality rate is one death in about every 2.57 million workouts." Two of the deaths occurred in nonmembers. Because the researchers had no information on these two individuals' previous workout histories, they were excluded from the rest of the study analysis. Among the 69 club members who died, 34 exercised less than once a week; 16 worked out one or two days a week; another 16 exercised three to four days; and three exercised five times or more weekly. The average age of those who died was 52.5 years, compared to an average age of about 30 for all the fitness club members. Sixty-one men and 10 women died, although the fitness clubs have almost an equal number of male and female members.

"So, the risk, relatively speaking, is higher in men," he says.

Franklin offers these recommendations: "Work out more regularly because it appears that people who are more regular attendees are less likely to experience exercise-related cardiovascular complications. Also, it's likely that the people who died had been exercising at an excessive intensity and may have avoided their cardiac problem had they been exercising less vigorously."

Depending on an individual's age, risk factors, symptoms and medical history, Franklin recommends a physical examination and possibly an exercise stress test before beginning a program of "vigorous" exercise, which the American College of Sports Medicine defines as greater than 60 percent of a person's capacity.
Co-authors are Jason M. Conviser, Ph.D.; Bob Stewart, M.B.A.; Judie Lasch, and Gerald C. Timmis, M.D.

NR00-1185 (SS2000/Franklin)

American Heart Association

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