Chronic obstructive pulmonary disease, or COPD, is the fourth leading cause of death in the United States, claiming 120,000 lives each year.

COPD is a serious lung disease that over time makes it hard to breathe. More than 12 million Americans have been diagnosed with COPD, and another 12 million likely have the disease and don’t even know it, according to the National Heart, Lung and Blood Institute, or NHLBI.

The NHLBI launched COPD Learn More Breathe Better, a national campaign designed to improve awareness of COPD.

The campaign offers four things that everyone needs to know about the disease.

Risk factors

You could be at risk for COPD if you:

• Can’t perform simple tasks you used to be able to do, like climbing stairs, grocery shopping or walking to the mailbox.

• Are over 40 and smoke or used to smoke.

• Have worked or lived around chemicals or fumes.

• Have certain genetic conditions.

If this sounds like you, it’s important to let your doctor know and make regular appointments, even if you’re feeling fine.

Symptoms

Shortness of breath, “smoker’s cough” and wheezing are all symptoms of COPD. The disease develops slowly, so it’s important to report symptoms to your doctor right away, no matter how mild they seem.

Breathing test

Ask your doctor about a breathing test.

If you think you might be at risk for COPD, talk to your doctor about a simple breathing test called spirometry that is used to diagnose the disease. It involves breathing out as hard and fast as you can into a tube connected to a machine that measures your lung function.

Follow treatment advice

If you are diagnosed with COPD, there is hope. You can take steps to make breathing easier and live a longer and more active life:

• Take medication as directed by your doctor.

• Enroll in a pulmonary rehabilitation program.

• Avoid pollutants or fumes that can irritate your lungs.

• Get flu and pneumonia shots as directed by your doctor.