The perception of breathlessness varies between individuals. This is a well-established concept in asthma, but mostly unexplored in COPD; the relationship between airflow limitation (FEV1, % ref.) and breathlessness (mMRC) is weak.~The perception of breathlessness varies significantly among COPD patients with similar severity of airflow limitation; those with poorer perception report less exacerbations as compared to those with frequent exacerbations.~It is a cross-sectional comparison of breathlessness perception in COPD patients with frequent exacerbations (≥2 or ≥1 with hospitalization in the previous year) or without frequent exacerbations (0 or 1 without hospitalization in the previous year).~To assess Breathlessness Perception the investigators will increase the ventilatory demand of the patients by CO2-rebreathing method. CO2 rebreathing test will be conducted to evaluate the acute ventilatory response to CO2 inhalation used to estimate central chemoreceptor responsiveness in patients with the obstructive pulmonary disease.~Simple descriptive statistics (unpaired T-test) and correlation analysis (bivariate and multivariate) will be used to analyze results.
The perception of breathlessness varies significantly among COPD patients with similar severity of airflow limitation; those with poorer perception report less exacerbations as compared to those with frequent exacerbations.~Cross-sectional comparison of breathlessness perception in COPD patients with frequent exacerbations or without frequent exacerbations.~To assess Breathlessness Perception the investigators will increase the ventilatory demand of the patients by CO2-rebreathing method.