Chronic obstructive pulmonary disease (COPD) is the fifth leading cause of death in the United States. Although many people think first of emphysema when they hear COPD, chronic bronchitis is actually more common and equally serious.

Shortness of breath may have prompted you to see the doctor. In many cases, though, COPD progresses for years without obvious symptoms.

If you cough up mucus and feel short of breath for at least three months each year, two or more years in a row, you have chronic bronchitis.

Emphysema is a lung disease that limits the movement of air into and out of your lungs, making it harder to breath.

COPD develops slowly, and people are often not diagnosed with it until their 50s, when the disease has greatly affected their lung function.

You take an average of 16 breaths every minute. It's a reflex—you don't pay attention unless there's a problem. But a rising number of us literally can't catch our breath.

As someone with COPD, you may find it helpful to know about the four components of care described in the GOLD guidelines.

A short glossary of terms associated with chronic obstructive pulmonary disease.