02/20/2026
What is COPD (chronic obstructive pulmonary disease)?
COPD (chronic obstructive pulmonary disease) is a group of lung diseases that make it hard to breathe and get worse over time.
Normally, the airways and air sacs in your lungs are elastic or stretchy. When you breathe in, the airways bring air to the air sacs. The air sacs fill up with air, like a small balloon. When you breathe out, the air sacs deflate, and the air goes out. If you have COPD, less air flows in and out of your airways because of one or more problems:
The airways and air sacs in your lungs become less elastic
The walls between many of the air sacs are destroyed
The walls of the airways become thick and inflamed
The airways make more mucus than usual and can become clogged
COPD (chronic obstructive pulmonary disease) makes it hard for you to breathe. At first symptoms are mild, but usually become more severe. Learn more.