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

Physiol Res. 2018 Dec 18;67(6):863-874. doi: 10.33549/physiolres.933867. Epub 2018 Sep 11.

Abstract

Chronic obstructive pulmonary disease (COPD) is a progressive and disabling disease that has been associated with aging. Several factors may potentially impair performance during exercise in elderly patients with COPD. This study was conducted to evaluate what characteristics related to lung function, peripheral muscle strength and endurance can predict the performance of elderly patients with COPD during cardiopulmonary exercise testing (CPET). Forty elderly patients with COPD underwent resting lung function tests, knee isokinetic dynamometry, and CPET. Three models were developed to explain the variability in peak oxygen uptake (VO(2) peak) after controlling for age as an independent confounder. The pulmonary function model showed the highest explained variance (65.6 %); in this model, ventilation distribution (p<0.001) and pulmonary diffusion (0.013) were found to be independent predictors. Finally, the models that included the muscle strength and endurance variables presented explained variances of 51 % and 57.4 %, respectively. In these models that involved muscular dysfunction, however, only the endurance variables were found to be independent predictors (p<0.05). In conclusion, ventilation distribution and pulmonary diffusion, but not the degree of airway obstruction, independently predict CPET performance in elderly patients with COPD. In addition, peripheral muscle endurance, but not strength, also predicts CPET performance in these subjects.

MeSH terms

  • Aged
  • Cross-Sectional Studies
  • Exercise Test / methods*
  • Exercise Tolerance / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Muscle Strength / physiology*
  • Oxygen Consumption / physiology
  • Physical Endurance / physiology*
  • Pulmonary Diffusing Capacity / methods
  • Pulmonary Diffusing Capacity / physiology*
  • Pulmonary Disease, Chronic Obstructive / diagnosis
  • Pulmonary Disease, Chronic Obstructive / physiopathology*
  • Pulmonary Ventilation / physiology*
  • Respiratory Function Tests / methods