Chief study author at Mayo Clinic: 'Though this was a cardiac stress test, we found that cancer was the leading cause of death'

A new study at the Mayo Clinic found that abnormalities in exercise stress tests with electrocardiogram (ECG), such as low functional aerobic capacity, predicted non-cardiovascular causes of death such as cancer in addition to cardiovascular-related deaths, a Sept. 6 Mayo Clinic news release said. The new findings have been published in Mayo Clinic Proceedings.

"In our exercise testing cohort, non-cardiovascular deaths were more frequently observed than cardiovascular deaths," said Thomas Allison, Ph.D., M.P.H., director of Mayo Clinic's Integrated Stress Testing Center and the study's senior author. "Though this was a cardiac stress test, we found that cancer was the leading cause of death at 38%, whereas only 19% of deaths were cardiovascular."

"Exercise test results, including low exercise capacity, low peak heart rate, and a slow recovery of the heart rate after exercise test were associated with increased mortality," he said in the press release.

The news release said 13,382 patients were included in the study. All of them completed the treadmill exercise test with electrocardiogram (ECG) between 1993 and 2010. Typically, the exercise test is used to diagnose coronary artery disease. Researchers followed study participants closely for a median period of 12.7 years.

Apart from the electrocardiogram (ECG) results, the test generates information about functional aerobic capacity, heart rate recovery, and the chronotropic index, a standardized measure of heart rate during exercise that considers age, resting heart rate, and fitness level, the release said.

The results indicate that healthcare providers should not place emphasis solely on ECG outcomes but also on exercise test data, particularly when aerobic capacity is low, the chronotropic index is low or heart rate recovery is abnormal. Dr. Allison said patients should be encouraged to boost their physical activity levels if these metrics appear unusual, regardless of whether the ECG results do not reveal substantial cardiovascular-related risks, according to the press release.