It isn't clear exactly what causes exercise-induced asthma, and why some people get it and others don't. In susceptible individuals, symptoms may be triggered by drying or cooling of the airways during heavy breathing.

Factors that can trigger or worsen exercise-induced asthma include:

  • Cold air
  • Dry air
  • Air pollution such as smoke or smog
  • High pollen counts
  • Having a respiratory infection such as a cold
  • Chemicals, such as chlorine in swimming pools

There's no particular exercise you must avoid when you have exercise-induced asthma, but activities that make you breathe hard are more likely to trigger symptoms. For example, aerobic exercise, such as running or playing basketball, hockey or soccer, is more likely to trigger symptoms than is weightlifting, golfing or moderate-paced walking. Likewise, exercising in cold weather also can increase asthma symptoms because you're breathing in a lot of cold, dry air.

But don't let that discourage you. With proper treatment, you can do intense aerobic activities — and cold-weather workouts — without asthma symptoms slowing you down.

Nov. 08, 2011