Ventilation distribution, pulmonary diffusion and peripheral muscle endurance as determinants of exercise intolerance in elderly patients with chronic obstructive pulmonary disease.

摘要

Chronic obstructive pulmonary disease (COPD) is a progressiveand disabling disease that has been associated with aging.Several factors may potentially impair performance duringexercise in elderly patients with COPD. This study was conductedto evaluate what characteristics related to lung function,peripheral muscle strength and endurance can predict theperformance of elderly patients with COPD duringcardiopulmonary exercise testing (CPET). Forty elderly patientswith COPD underwent resting lung function tests, knee isokineticdynamometry, and CPET. Three models were developed toexplain the variability in peak oxygen uptake (VO2 peak) aftercontrolling for age as an independent confounder. Thepulmonary function model showed the highest explained variance(65.6 %); in this model, ventilation distribution (p0.001) andpulmonary diffusion (0.013) were found to be independentpredictors. Finally, the models that included the muscle strengthand endurance variables presented explained variances of 51 %and 57.4 %, respectively. In these models that involved musculardysfunction, however, only the endurance variables were foundto be independent predictors (p0.05). In conclusion, ventilationdistribution and pulmonary diffusion, but not the degree ofairway obstruction, independently predict CPET performance inelderly patients with COPD. In addition, peripheral muscleendurance, but not strength, also predicts CPET performance inthese subjects.