Asthma

What is Asthma?

Asthma is a chronic (long-term) disease that makes it hard to breathe. At its worst, asthma can be fatal. For example, in 2003, asthma killed 287 Canadians. Asthma can’t be cured, but it can be managed. With proper treatment, people with asthma can lead normal, active lives.

If you have asthma, your airways (breathing passages) are extra sensitive. When you are around certain things, your extra-sensitive airways can:

Become red and swollen – your airways get inflamed inside. They fill up with mucus. The swelling and mucus make your airways narrower, so it’s harder for the air to pass through.

Become “twitchy” and go into spasm – the muscles around your airways squeeze together and tighten. This makes your airways narrower, leaving less room for the air to pass through.

The more red and swollen your airways are, the twitchier they become.

Doctors define asthma as a “chronic reversible inflammatory disease of the airway” that causes the following symptoms:

  • Shortness of breath
  • Tightness in the chest
  • Coughing
  • Wheezing

Asthma has no set pattern. Its symptoms:

  • Can be mild, moderate or severe
  • Can vary from person to person
  • Can flare up from time to time and then not appear for long periods
  • Can vary from one episode to the next

The cause of asthma is not known, and currently there is no cure. However, there are many things you can do so you can live symptom-free.

asthma diagram

Predicted Mean Values for Healthy Adults ( 20 kb pdf)