A Comparison of Conventional Versus Anaerobic Threshold Exercise Prescription Methods in Subjects With Left Ventricular Dysfunction

Abstract

This study compared conventional exercise prescription methods with an anaerobic threshold (AT) method in a population with left ventricular dysfunction (LVD) to determine: 1) if a significant number of conventionally prescribed training heart rate ranges (THR) were above anaerobic threshold; and 2) if there was a significant decrease in ventricular function at the prescribed heart rate ranges as assessed by Doppler ultrasound variables, ascending aortic blood velocity (AABV) and peak acceleration (PA). The sample consisted of twelve male subjects with documented LVD (ejection fraction < 40%) and 12 age-matched control subjects with no history of coronary artery disease. All subjects underwent a treadmill-graded exercise test (GXT). Four different exercise prescriptions were then written. Results showed that in a significant number of patients with LVD (69.4%), conventional THR ranges were beyond the AT (P < 0.001). Changes in AABV and PA showed no significant differences at the lower end of training ranges (LTR). At the higher end of the training ranges, a significant decrease (P < 0.05) was found in PA with all conventional prescription methods versus the AT method (8.7% average). Ascending aortic blood velocity changes showed a significant difference at the higher end of the training ranges for only the heart rate reserve method. This study suggests that conventional exercise prescription methods used on patients with LVD lead to a significant number of THR ranges that are beyond AT and optimal ventricular function.