COPD, or chronic obstructive pulmonary disease, is a progressive disease, which means it gets worse over time. With COPD, less air flows in and out of the airways, making it hard to breathe.

COPD Basics (3:52)
Learn who is at risk for COPD, what symptoms to watch for, and how the disease affects the lungs. 


In the United States, COPD affects more than 15 million adults, and many more do not know they have it. More than half of those diagnosed are women. COPD is a major cause of disability, and it is the fourth leading cause of death in the United States according to the Centers for Disease Control and Prevention (CDC).

The good news is that COPD can often be prevented, mainly by not smoking. Cigarette smoking is the leading cause of COPD. Most people who have COPD smoke or used to smoke. However, up to 30% of people with COPD never smoked. A rare genetic condition called alpha-1 antitrypsin (AAT) deficiency can also cause the disease.

In the United States, the term COPD includes two main conditions.

  • Emphysema develops when there’s damage to the walls between many of the air sacs in the lungs. Normally, these sacs are elastic or stretchy. When you breathe in, each air sac fills up with air, like a small balloon. When you breathe out, the air sacs deflate, and the air goes out. In emphysema, it is harder for your lungs to move air out of your body.
  • Chronic (long-term) bronchitis is caused by repeated or constant irritation and inflammation in the lining of the airways. Lots of thick mucus forms in the airways, making it hard to breathe.

Most people who have COPD have both emphysema and chronic bronchitis, but how serious each condition is varies from person to person.

COPD can cause coughing that produces large amounts of a slimy substance called mucus. It can also cause problems breathing, shortness of breath, chest tightness, and other symptoms. Symptoms of COPD often develop slowly but worsen over time, and they can limit your ability to do routine activities. Serious COPD may prevent you from doing even basic activities like walking, cooking, or taking care of yourself.

Although there is no cure, treatments and lifestyle changes such as quitting smoking can help you feel better, stay more active, and slow the progress of the disease. You may also need oxygen therapy, pulmonary rehabilitation, or medicines to treat complications.

copd lung

A Quick Guide on COPD

This guide provides an overview of COPD and its symptoms.

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