Determination of exercise training level in coronary artery disease patients on β blockers

Objectives To compare the intensity of three exercise training regimens. Background During a cardiac rehabilitation program coronary artery disease (CAD) patients should be trained at an intensity as close as possible to the ventilatory threshold (VT) level. The precise way to obtain this intensity of training during the sessions, however, remains unclear. Methods In stable beta-blocked CAD patients, heart rate (HR) and workload (WL) at the VT were determined from a cardiopulmonary exercise test. The 3 following days, each patient performed (in a randomized order) one bicycle training session per day at an intensity determined by (i) HR at VT, (ii) WL at VT, (iii) patient's feelings (14 on the Borg scale). HR, WL, systolic blood pressure, oxygen consumption (V-O2) and the respiratory exchange ratio were monitored during each session, to compare the intensity of each regimen. Results Twenty patients, 57 +/- 10 years old were included. V-O2, WL, HR and systolic blood pressure were significantly higher in the sessions driven by feelings and WL, than in the HR-driven sessions. As respiratory exchange ratio remained less than 1, we can assume that there was no important and deleterious participation of anaerobic metabolism. Conclusion Classical training HR prescription could lead to undertrain CAD patients, although a training session prescription driven by the feelings or by the WL observed at VT allows the patients to train at a higher - but still aerobic - intensity.