Health Information

How COPD Affects the Lungs


The term COPD includes conditions such as emphysema and chronic bronchitis, the American Lung Association says. Each of these conditions prevents the lungs from working properly.

Airway swelling

All people who have COPD develop swelling in the airways. This decreases the airways’ natural elasticity, restricts the flow of air through the airways, and limits lung capacity.

With emphysema, the walls between air sacs in the lungs disintegrate, leaving fewer, larger sacs. These fewer sacs don’t have as large a surface area to exchange oxygen and carbon dioxide, so they aren’t efficient. People with emphysema are short of breath during physical activity and may be short of breath even at rest.

In chronic and asthmatic bronchitis, the airways have become inflamed and thickened. The linings of the airways produce too much mucus, which builds up, leading to coughing and difficulty breathing. The muscles that surround the lungs’ airways may tighten when they shouldn’t. This can cause airways to narrow, making it harder to breathe.

Smoking danger

COPD and smoking have a clear connection, according to the National Heart, Lung, and Blood Institute. Cigarette smoke is the most common cause of COPD cases in the United States. Pipe, cigar, and other types of tobacco smoke also can cause COPD, especially if smoke is inhaled. People exposed to air pollution, chemical fumes, vapors, and mineral and organic dust for long periods of time also are at risk.

Signs and symptoms

COPD develops slowly, and it can take many years before you notice any of these symptoms:

  • Shortness of breath, especially during exercise

  • Coughing up mucus

  • Wheezing

  • A cough that doesn’t go away

  • Tightness in the chest

If you have any of these symptoms, it doesn’t mean you have COPD, but you should see your health care provider for an evaluation.


COPD can't be cured, but you can take steps to keep your symptoms under control and slow the disease’s progress. The most important step you can take is to quit smoking and avoid secondhand smoke.

Your health care provider or a lung specialist will suggest treatments based on the seriousness of your condition.