The triggers responsible for exercise-induced asthma differ from person to person. Typically, though, it is most likely to occur during prolonged, intense exercise in a cool, dry environment.

Allergens and pollutants inhaled during exercise often trigger symptoms. If pollen is known to trigger asthma in a person, then exercising on a grassy field is likely to put that individual at risk for an attack.

Those exercising on a busy street might find that excess air pollution triggers symptoms. Recent studies have shown that air pollution can have a significant effect on a person's lungs. Specifically, research suggests that certain pollutants can trigger bronchoconstriction (tightening in the airways) in sensitive individuals, making it more difficult to breathe. Depending on the area, exercising outside may bring a person into contact with air pollutants and increase the chance of bronchoconstriction or an asthma attack.

In addition, pollutants can trigger bronchospasm. They can also make a person more sensitive to another trigger that would not cause a reaction alone, or might cause a smaller reaction alone.   

In some individuals, it appears that foods eaten several hours prior to exercise can increase the likelihood of an attack. A condition called exercise-induced anaphylaxis tends to occur when a person eats certain foods, and subsequently exercises in hot, humid conditions. Intensity of exercise also may be a factor in triggering this condition. Foods that can provoke a life-threatening reaction include:

• Shrimp
• Celery
• Peanuts
• Egg whites
• Almonds
• Bananas

Cold air alone can be enough to trigger EIA. For this reason, people with the disorder must be careful when exercising outdoors during the winter months.