
Up to 80% of kids with asthma have symptoms when they exercise. It makes sense that cigarette smoke and pollen could trigger asthma symptoms, but why exercise?

Cold, dry air that's inhaled during exercise is believed to be the main cause of these symptoms. When kids exercise or play strenuously, they tend to breathe quickly, shallowly, and through the mouth. So the air reaching their lungs misses the warming and humidifying effects that happen when they breathe more slowly through the nose.
The cool, dry air causes the airways in the lungs to become narrower, which blocks the flow of air and makes it harder to breathe. This narrowing, called bronchoconstriction, occurs in up to 20% of people who don't have asthma, which is why it's sometimes referred to as "exercise-induced bronchoconstriction (EIB)" rather than "exercise-induced asthma (EIA)."
Symptoms
Symptoms of exercise-induced asthma include wheezing, tightness or pain in the chest, coughing, and in some cases, prolonged shortness of breath. Some symptoms are more noticeable than others, which means exercise-induced asthma can sometimes go undiagnosed.
Someone may have exercise-induced asthma if he or she:
- gets winded or tired easily during or after exercise
- coughs after coming inside from being active outdoors
- can't run for more than a few minutes without stopping
Kids with exercise-induced asthma often begin having symptoms 5 to 10 minutes after starting to exercise. Symptoms usually peak 5 to 10 minutes after stopping the activity and may take an hour or longer to end. Some people with EIA even have symptoms for hours after exercise. Although symptoms often appear while kids are active, sometimes they can appear only after the activity has stopped.
Of course, there's a difference between someone with exercise-induced asthma and someone who's out of shape and is simply winded. Out-of-shape people can catch their breath within minutes, whereas it takes much longer for someone with EIA to recover. And extremes of temperature, especially cold weather, can make it even worse.
Diagnosing EIA
A doctor who suspects exercise-induced asthma will ask about the family's asthma and allergy history and about the symptoms and what has triggered them in the past.
After taking a detailed history and performing a physical exam, the doctor may ask your child to perform a breathing test after exercising. This can be done in the office on a treadmill, after your child has run outside for 6 to 8 minutes, or after participating in whatever activity has triggered flare-ups in the past.