Continuous Versus Interval Training in Patients With Coronary Artery Disease: FRAXIO Study

Overview

The benefits of cardiac rehabilitation have been clearly demonstrated. In particular exercise training is recognized to be part of modern management after coronary artery disease. However methods of prescribing exercise-training programs and the exercise intensity are difficult to determine. The objective of this randomised clinical trial is to determine whether appropriate endurance exercise training improves the ventilatory threshold, the exercise tolerance and the quality of life in patients with coronary artery disease. Patients are randomized to continuous training or aerobic interval training respectively: 80%-versus maximal-workload at the ventilatory threshold. For each patient, the intensity of exercise training is determined by a first exercise test with gas analysis using parameters of sub maximal exercise capacity such as ventilatory threshold. Others parameters of functional capacity are also considered. Duration of the rehabilitation stage is between 7 to 10 weeks. Dyspnoea assessment at maximal intensity, quality of life measurement by SF36, drugs and events are reported. Maximal exercise tests with gas exchange measurements are performed after training program and at 6 months follow-up to compare the different cardio respiratory parameters in the two groups before and after exercise training and to evaluate the more effective endurance training program.

* Outline of the training program: Duration of the rehabilitation course is 7 or 10 weeks, 2 or 3 training sessions a week, 21 sessions altogether. Each training session consist in cycling on an ergometer. In the interval training group, the training session alternates one minute at 100% workload at the ventilatory threshold and one minute active pause at 50% workload at the ventilatory threshold; total exercise time is 20 minutes. In continuous training, the training session lasts 20 minutes at 80% workload at the ventilatory threshold. * Exercise testing: Exercise capacity is measured before and at the end of the exercise training program and at 6 month follow-up. A first exercise test with respiratory gas exchange is performed 2 weeks after hospitalization: this is the baseline exercise test. The protocol consists of 3-min warm up at a workload of 30 watts. At each stage, the workload is increased by 10 or 15 watts per min. Patients are instructed to maintain a speed of 55 to 65 rotations per min. Four exercise tests with gas analysis are programmed during cardiac rehabilitation: three maximal tests (before exercise training program to precise exercise intensity during the sessions, after training program to evaluate the primary end point and at 6 months) and one sub maximal exercise test during the tenth session to adjust the intensity of training exercises (this test is stopped when the ventilatory threshold is obtained).