Reduced "exercise capacity" an ominous sign
NEW YORK (Reuters Health) - People who have trouble exercising on a treadmill are at increased risk of suffering a heart attack or other heart-related event and of dying, according to results of a study.
"Exercise capacity" is one of many important prognostic factors measured during an exercise treadmill test, a simple procedure often performed in doctors' offices. But "little is known about the association between exercise capacity among patients referred for exercise treadmill testing and nonfatal cardiac events," Dr. Pamela N. Peterson, of the University of Colorado at Denver and Health Sciences Center, and colleagues note in a report.
Among 9191 adults who had a treadmill test and who were followed for a median of 2.7 years, 119 were hospitalized for heart attack and 259 for chest pain. Moreover, 749 required revascularization procedures to restore blood flow to the heart, and 132 patients died.
According to Peterson's team, people with low exercise capacity, relative to those with normal exercise capacity, on the treadmill test, had more than a twofold increased risk of having a heart attack, experiencing chest pain, or needing a revascularization procedure.
Low exercise capacity was also significantly associated with an increased risk of dying from any cause.
Peterson's team also found that individuals with lower exercise capacity were more likely to be female and to have other comorbid conditions such as diabetes and high blood pressure compared to individuals with greater exercise capacity.
Those with lower exercise capacity were also more likely to have chest pain on the treadmill and abnormal heart rate recovery -- a measure of how quickly the heart rate returns to normal after a period of exercise.
The findings have important implications, the researchers conclude, suggesting that "aggressive risk factor modification and close follow-up should be considered for patients with impaired exercise capacity."
SOURCE: Archives of Internal Medicine, January 28. 2008.