What Is Chronic Bronchitis?

Chronic bronchitis occurs when damaged lungs produce more mucus than they should. 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.

Healthy Lungs

• Inside the lungs are branching airways of stretchy tissue. Each airway is wrapped with bands of muscle that help keep it open. Air travels in and out of the lungs through these airways.

• The cells in the lining of the airways produce a sticky fluid called mucus. This traps dust, smoke, and other particles in the air you breathe.

• Tiny hairs, called cilia, then sweep the mucus up the airways to the throat, where it is swallowed or coughed up.

When You Have Chronic Bronchitis

• Cells in the airways make more mucus than normal. The mucus builds up, narrowing the airways. This means less air travels into and out of the lungs.

• The lining of the airways may also become inflamed (swollen). And, the muscle surrounding the airways may constrict (tighten). These problems cause the airways to narrow even more.

• The cilia may also be damaged. This means they can’t sweep mucus and particles away. This damage makes the problems described above even worse.