Improved breathing capacity during exercise in severe obstructive airway disease

Respir Physiol. 1998 May;112(2):145-54. doi: 10.1016/s0034-5687(98)00024-3.


In severe COPD, ventilation at peak exercise may exceed the resting maximal voluntary ventilation (MVV). We investigated the mechanisms by which the breathing capacity can improve during exercise in COPD. A total of 13 patients with an FEV1 of 32+/-12% (SD) predicted, performed an incremental maximal exercise test and FVC and MVV maneuvers at rest and during constant work rate exercise. Maximal exercise ventilation was 3+/-2 L/min higher than resting MVV. Breathing capacity improved during exercise; resting MVV was 30+/-3 (SE) L/min, while it reached 38+/-3 L/min during exercise (P < 0.002). FEV1 improved from 0.86+/-0.1 L at rest to 1.01+/-0.1 L during exercise (P < 0.004), which is consistent with exercise-induced bronchodilatation. It is concluded that in severe COPD, breathing capacity improves during exercise. Assuming that the change in FEV1 reflects improved airway function, these data suggest that exercise-induced bronchodilatation contributed to that improvement.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Bronchi / physiopathology
  • Exercise / physiology*
  • Exercise Test
  • Female
  • Forced Expiratory Volume / physiology
  • Humans
  • Lung Diseases, Obstructive / physiopathology*
  • Male
  • Maximal Voluntary Ventilation / physiology
  • Middle Aged
  • Pulmonary Ventilation / physiology
  • Respiratory Mechanics / physiology*
  • Respiratory Muscles / physiopathology