Chronic obstructive pulmonary disease (COPD) is a common disease characterized by progressive airflow limitation and tissue destruction. It’s most commonly caused by smoking and is seen in people over the age of 40. The disease is linked with ongoing airway limitation and inflammation. It causes problems with breathing, especially breathing air out of the lungs, and problems with the exchange of oxygen and carbon dioxide within the lungs. Other problems that may be caused by the disease are changes to the breathing mechanics (pattern), breathlessness, reduced heart function, problems with skeletal muscles and lower overall fitness. Usually, the most common