[Evaluation of dynamic hyperinflation parameters and exercise capacity at maximal exercise in patients with COPD]

Hyperinflation is an important limiting factor for exercise performance in patients with chronic obstructive pulmonary disease (COPD). Hyperinflation can be determined by measuring residual volume (RV), functional residual capacity (FRC), and total lung capacity (TLC) at rest, and by measuring inspiratory capacity (IC) and end-expiratory lung volume (EELV) at maximal exercise. This study aimed to evaluate changes in hyperinflation parameters on maximal exercise in subjects with COPD. Patients with clinically stable COPD (n= 43) and healthy controls (n= 14) were included. Subjects performed pulmonary function tests and an incremental exercise test on cycle ergometry. Statistically significant differences (p< 0.05) were found regarding exercise test parameters including exercise duration, maximum oxygen uptake, breathing reserve, maximum minute ventilation, and breathing pattern between groups. There was significant increase in EELV (p< 0.05) and decrease in IC (p< 0.05) at maximum exercise when hyperinflation parameters were compared at baseline and maximum exercise. Our results showed that hyperinflation was evident at maximal exercise, although there were no hyperinflation findings at rest in subjects with COPD. We believe that in patients with COPD, it is better to evaluate hyperinflation at maximal exercise than at rest.