Chronic obstructive pulmonary disease (COPD) is a condition in which some of your airways are permanently blocked. COPD makes it harder for you to breathe. It causes strain on and enlargement of your heart (cor pulmonale) and increased blood pressure in your lungs (pulmonary hypertension).

There are 2 main types of COPD: chronic bronchitis (inflamed airways) and emphysema (damage to the lung tissue). Chronic bronchitis and emphysema result from irritation of your airways over a long time, usually from smoking and sometimes from air pollution. Other causes are on-the-job exposure to irritants such as dust or chemicals, or frequent lung infections.

Chronic bronchitis and emphysema can occur separately but often they develop together. In chronic bronchitis, the insides of the airways thicken and swell. This makes the passageway for air inside the airways smaller. The damaged airways make more mucus, which can block the airways and make it hard to breathe. In emphysema, the tiny air sacs in the lungs may become badly damaged or destroyed and lose their ability to stretch. This makes it harder for you to breathe out after breathing in. This makes less room for oxygen to be breathed into your lungs.

COPD is not contagious. You cannot give it to someone or get it from someone else.