Breathe more easily for more of your day
What is COPD?
Facts you should know
COPD (Chronic Obstructive Pulmonary Disease) is a condition that makes it harder for people to breathe. It includes 2 different diseases: chronic bronchitis and emphysema. To understand what happens in COPD, let's look at how the lungs work.2
How the lungs work
The lungs deliver oxygen (O2) to the blood and allow carbon dioxide (CO2) to be removed from the blood when you exhale. When we breathe in, air goes down the windpipe into the lungs. Passageways, called bronchial tubes or airways, carry the air to all parts of the lungs.2 As they branch out, the bronchial tubes get smaller and smaller. They end in groups of tiny air sacs. Oxygen passes through the thin walls of the air sacs into the blood. CO2 passes from the blood back into the lungs to be 
exhaled.2
Chronic bronchitis
Chronic bronchitis is a swelling of the airways. It develops slowly over the years. After a while, the bronchial tubes become scarred and thickened. A thick mucous is produced. This makes it harder to get air into the lungs.2
Emphysema
In emphysema, the walls of the air sacs no longer stretch easily. As the air sacs become brittle and their walls break down, they are less able to get bigger and smaller and pass less oxygen into the blood or remove CO2 from the blood.2 Emphysema and chronic bronchitis frequently coexist in COPD.3