Chronic Obstructive Pulmonary Disorder (COPD)

Basic Facts

What is COPD?

Chronic obstructive pulmonary disorder (COPD) is a long-term illness in which airflow out of the lungs is obstructed, causing difficulty breathing. 

COPD is a progressive disease. This means that symptoms will gradually get worse over time. There is no cure for COPD, but there are treatments that can control symptoms, reduce flare-ups, and help people with the disease maintain a good quality of life.

The Most Common Types of COPD

COPD includes two diseases: emphysema and chronic bronchitis. Many people with COPD have both conditions. 


When you breathe in, air flows in through your trachea (windpipe) into smaller and smaller branches of airways, and finally into the alveoli. Alveoli are tiny air sacs in the lungs where the oxygen you inhale gets taken up into the bloodstream. The alveoli exchange the oxygen for carbon dioxide, a normal waste product that is exhaled. Normally, alveoli work like little balloons, expanding with air when you inhale, and contracting to push air out when you exhale.  

With emphysema, the alveoli become less elastic – more like plastic grocery bags than balloons - and the small airways leading to them start to collapse. This causes air to get “trapped” in your lungs, making it hard to breathe out. With emphysema, alveoli also become damaged and destroyed, leading to empty spaces or holes where the air sacs should be. With fewer and fewer healthy alveoli it becomes harder and harder to breathe.

The earliest symptom of emphysema is dyspnea (shortness of breath). This happens slowly so many people don’t notice any change. Sometimes people think that becoming short of breath is a normal part of aging and may not mention it to their healthcare provider. If you notice that you have become more short of breath over time, or now become short of breath with activities that you used to be able to do without difficulty, let your healthcare provider know. 

Chronic bronchitis

Chronic bronchitis is a long-term irritation and inflammation of the branching airways that carry oxygen into your lungs and carbon dioxide back out. When the airways are irritated, they produce excessive amounts of mucus. This extra mucus can build up in the airways, blocking the flow of air. Ongoing (chronic) irritation and inflammation also cause the walls of the airways to get thicker. This makes the airway narrower, further obstructing the flow of air. The airways can become scarred from irritation and inflammation, making it harder for them to heal. 

The symptoms of chronic bronchitis are a cough that brings up mucus and lasts at least 3 months. The cough may go away then come back again.

How Common is COPD?

COPD is common. In the U.S., about 5% of the population has COPD. Among adults age 75 years and older, about 10% of the population has COPD.  Many more people have COPD but have not been diagnosed. About 120,000 people die from COPD each year, making it the fourth leading cause of death in the U.S. COPD is also a leading cause of hospitalization. About 20% of hospitalizations for adults over age 65 are due to COPD.


Last Updated August 2020