Purpose: To create a maximum tolerated 45-minute aerobic training program for patients with chronic obstructive pulmonary disease (COPD) and to compare its outcomes with those of commonly prescribed moderate exercise.
Design: Prospective, randomized trial.
Setting: A work physiology laboratory.
Patients and methods: The maximum exercise intensities that 7 COPD patients could sustain for 45 minutes were determined on a bilevel exercise ergometer. The patients then exercised 45 minutes daily, 5 days a week for 6 weeks, working 2.03+/-0.4 kJ/kg per session. They were matched with 6 COPD patients who pushed an O2 cart for 45 minutes daily, 5 days a week for 6 weeks, working 1.44+/-.35 kJ/kg per session.
Results: A 45 minute maximal regimen was established by alternating 1-minute peak exercise at peak VO2-levels with 4 minutes at the ventilatory anaerobic threshold or at 40% of peak VO2. Maximal bilevel training significantly decreased dyspnea at rest (p< or =.01) and the blood lactate level during submaximal exercise (p<.001), and increased peak VO2 and total physical work (p<.01), maximum inspiratory and expiratory pressures (p<.01), and grip and forearm strength and endurance (p<.01). The training also increased maximum voluntary ventilation while decreasing the ventilatory equivalent during exercise (p<.001). The O2 cart pushers significantly improved only on the 12-minute walk (p<.05).
Conclusions: A maximally intense anaerobic exercise program can be created for most COPD patients that can significantly improve both skeletal and respiratory muscle strength and endurance as well as dyspnea and physiologic parameters.