Treadmill exercise training in chronic obstructive pulmonary disease.

Abstract

Eight men and six women with severe chronic obstructive pulmonary disease (COPD) performed a pulmonary function test and a treadmill exercise stress test before and after an individualized training program, which nominally consisted of three 20-minute sessions of treadmill exercise per week for five consecutive weeks. Training sessions were terminated before 20 minutes if there were subjective complaints, or if the subject's heart rate reached 80% of the maximum heart rate observed during the pretraining stress test. This program failed to improve any of the pulmonary function test parameters (lung volumes, airflows, maximum voluntary ventilation, and resting levels of blood gases) and failed to improve most exercise stress test parameters (maximum oxygen consumption and carbon dioxide production, respiratory exchange ratio, and heart rate at termination of exercise). This program, however, did increase the group's average stress test time from 9.0-13.7 minutes (p less than 0.001) and increased the total external work (calculated from the sum of its vertical and horizontal components) from 3.5-6.8kcal (p less than 0.01). Eight of the 11 subjects who initially received 2L/min of 100% oxygen, via a nasal cannula, to alleviate dyspnea and to promote endurance were completely weaned from supplemental oxygen by the end of the training program. These findings demonstrate that a treadmill exercise program based on stress test data can increase the efficiency (external work per unit of oxygen consumed) and thus, the exercise tolerance, of persons with severe COPD.