Emphysema is a condition in which there is over-inflation of alveoli or air sacs. This over-inflation results from a breakdown of the walls of the alveoli, which causes a decrease in respiratory function and often, breathlessness.

Early symptoms of emphysema include inflammation, shortness of breath (dyspnea), Hypoxemia, fatigue, low SaO2, and coughing.

Emphysema ranks ninth among chronic conditions that contribute to lack of activity: over 42% of individuals with emphysema report that their daily activities have been limited by the disease.