Bronchitis is when the walls of your bronchi, the tubes that carry air into and out of your lungs, become thickened and damaged. This makes it harder to breathe. You could have flare-ups of severe breathing problems (your doctor may call them exacerbation) from time to time.

Bronchitis is a long-term (or chronic) disease that gets worse over time. There’s no cure, but you can live with it for a long time. Your bronchial walls can slowly get thicker because of inflammation and infections.

Both of these things keep mucus from draining the way it should. That extra mucus can trap bacteria, causing more infections, scarring, and thickening. Over time, your lungs have to work harder to breathe.

Younger people don’t usually get bronchitis. Fewer than 1 in 20,000 people ages 18 to 34 have it. But that number goes up to about 1 in every 350 people who are 75 or older. Two-thirds of bronchitis cases are in women. But it’s more common in young boys than in girls.