Effect of Exercise Training on Multiple Respiratory Variables in Patients with Coronary Artery Disease: Correlation with Change in Exercise Capacity

Abstract

Multiple measurements of pulmonary function were performed during exer cise testing in 29 patients with coronary artery disease (CAD) before and after exercise training. Following training, significant increases in oxygen consump tion (VO 2), carbon dioxide production (VCO2), and peak flow at maximal exer cise were seen as compared with pretraining values (p < .01), but not in any other respiratory variables. Only the peak respiratory exchange ratio (RER) achieved during pretraining exercise testing and peak values of minute ventilation (VT), respiratory rate, and VCO2 during a posttraining exercise test showed signifi cant correlations with the change in maximum VO2 following exercise training (p<.05). Significant correlations were also found among VT, VCO2, and peak flow at peak exercise following exercise training and the change in exercise du ration between pretraining and posttraining stress tests. Of 22 patients evaluat ed with thallium 201 scintigraphy during their pretraining exercise test, 11 developed ischemic ST depression or a reversible perfusion defect. No signifi cant differences in pulmonary function measurements during exercise testing were seen between patients who developed ischemia and those who did not. However, the change in peak metabolic equivalents (METS) achieved between pretraining and posttraining exercise was significantly greater in patients who developed ische mia (.836±1.003 versus .091±.481, p<.05). These results indicate that exercise training in patients with CAD is not as sociated with significant changes in most measurements of pulmonary function and, with the exception of RER at peak exercise, pretraining measurements do no show a significant correlation with changes in exercise capacity.