[Effects of muscle training on breathing pattern in patients with severe chronic obstructive pulmonary disease]

During physical exertion, the ventilatory response of patients with severe chronic obstructive pulmonary disease (COPD) is more rapid and shallow than that of healthy subjects. There is evidence that exercise training can alter breathing pattern in COPD patients. The purpose of the present study was to observe the effects of physical training on patients with severe COPD and to determine whether or not any possible changes were maintained over time.

Patients with severe COPD without bronchial reversibility were enrolled in a randomized controlled trial of a peripheral muscle training program carried out in a hospital setting. All enrolled patients were clinically stable, without exacerbation, and were randomly assigned to a training program of high (group A) or low (group B) intensity.

Thirty-five men with severe COPD in stable condition (mean [SD] forced expiratory volume in 1 second at 41%[7%]) were enrolled in the study. The mean age was 64(5) years. Group A underwent training at 70(22) W and group B at 35(10) W, such that the estimated total work was 8050(2882) kJ in group A and 4044(1205) kJ in group B. Breathing pattern changes were detected in exercise tests only for group A patients, but the changes were not maintained 12 months after the end of the program.

Intense training produces changes in the breathing pattern of patients with severe COPD. The changes are not specific to the task performed, not dependent on lactate production, and not maintained over the long term.