Value of Taking Stress Test Before Exercise Is Doubted : Fitness: Cardiologist says such exams don’t predict well who will die during a workout, which is extremely rare in any event. And passing the test is no guarantee of safety, because problems can develop quickly later.
Do middle-aged men and women really need to pay a doctor $200 or more for a stress test before they take up exercise? A new report suggests that, for many, the test may be oversold.
A stress test is used to discover the intensity of effort that may produce heart irregularities. Subjects ride a bike, or walk, or jog on a treadmill at increasing intensity while their hearts are monitored on an electrocardiogram.
Although it’s commonly used on heart patients, a stress test can also be used as a screening tool on large numbers of people who have no outward sign of heart trouble to weed out those who may develop symptoms.
The American College of Sports Medicine recommends the test for apparently healthy but sedentary men over 40 and women over 50 who want to start a regimen of vigorous exercise, such as jogging 20 minutes or more at enough intensity to raise a sweat.
A noted researcher and cardiologist, however, believes that position is too broad.
“A lot of people think stress tests are the best thing since sliced cheese, but it doesn’t stand the test of time,” said Dr. Paul D. Thompson, director of preventive cardiology at the University of Pittsburgh.
Thompson concedes that many other heart experts think his stand is out of line: “Whenever I present this to other cardiologists, it’s like, ‘What moon did you just come from?’ ”
Stress tests don’t predict well who will die while exercising, and may give misleading results that lead to unnecessary tests, Thompson said. In any case, deaths while exercising are extremely rare, he said in the September issue of the ACSM journal Medicine and Science in Sports and Exercise.
Thompson noted one study in which men with high cholesterol took exercise tests annually for seven years. Only 4% of exercise-related heart problems in this group were predicted by the test, his article said.
“Even if you get a normal stress test, you are not home free,” Thompson said.
For example, coronary arteries narrow rather quickly in some people--after the stress test that cleared them for exercise, he said.
And so few people die of heart attacks while exercising that many people would have to be tested to spot those who would benefit, Thompson said.
Thompson did a study of male joggers 30-64 years old who had no known coronary artery disease. By examining death statistics for Rhode Island, he came up with a rate of seven deaths a year for every 100,000 joggers.
In contrast, the American Heart Assn. says the death rate for coronary heart disease among men ages 45-54 in 1990 approaches 124 per 100,000.
Stress test results also can be confusing, Thompson said. Trained athletes may have murmurs and slow heartbeats but be perfectly healthy, he said. But because those are troublesome signs in a non-athlete, a careful physician might order more tests--unnecessarily alarming the athlete and driving up the cost, he said.
Another expert sees some value in Thompson’s concern about the value of stress testing. But Dr. Sam Fox of Washington likes a test for sedentary middle-aged people with heart attack risk factors such as smoking.
“If the insurance doesn’t pay for it, it may be a better investment of discretionary income than a case of not-very-good whiskey,” said Fox, director of the preventive cardiology service at Georgetown University.
Thompson does not recommend that middle-aged would-be exercisers simply jump into vigorous workouts, however. He suggested that a good physical examination and a thorough medical history may be all the screening needed.
Doctors should first look for heart symptoms, such as discomfort in the chest under exertion, Thompson said. In one study, “about half the people who dropped dead had some symptoms they thought enough of to report to their spouse,” he said. “That’s when an exercise test becomes useful.”
