Figure 1

Pathogenetic mechanisms of dyspnea in smokers with COPD. Exposure to cigarette smoke is the major factor in the pathogenesis of COPD. Risks conferred by smoking interact with genetic susceptibility and respiratory infections to produce expiratory flow limitation (EFL) by loss of elastic recoil and airway inflammation. EFL, by producing hyperinflation and hyperinflation per se generate dyspnea sensation.