Dear Doctor: I've noticed that after running, especially when I've really pushed myself, I'll cough for a while. A friend says it's something called exercise-induced asthma. Why is it happening?
Dear Reader: Your symptoms are in line with something known as exercise-induced bronchoconstriction, often referred to as exercise-induced asthma. It usually happens after -- but sometimes during -- exercise that's vigorous enough to significantly increase your heart rate and respiration. In some people, this post-exercise period of coughing is accompanied by additional symptoms like a tight chest, shortness of breath or wheezing. In the majority of cases, these symptoms prove to be temporary and breathing returns to normal.
Asthma is a chronic disease in which the airways to the lungs become narrowed or inflamed, which interferes with breathing. This inflammation often makes people with asthma sensitive to a range of factors, including dust, mold, tobacco smoke, pollen, pet dander, air pollution, chemicals, certain medications, exertion and cold air. Known as triggers, these sensitivities can cause an asthma attack in which the airways become even more inflamed and symptoms worsen. In severe cases, an asthma attack can cause airways to become fully obstructed and can be fatal.
Unlike people with asthma, who have multiple triggers, those with exercise-induced asthma experience symptoms only during or after exertion. Some find that their episodes are associated with exercising in air that is colder or dryer than normal. The same workouts that produce no symptoms in the warmer months may bring on coughing and wheezing when the weather turns cold, or when indoor heating takes the moisture out of the air. In most people, symptoms start five to 20 minutes after beginning to exercise, or five to 10 minutes after exertion has ended, and are short-lived.
Diagnosis of exercise-induced asthma typically begins with a resting lung function test. This is done with a breathing device known as a spirometer, which measures the volume of your inhale, the volume of your exhale and how quickly you expel the air from your lungs. This may be followed by an exercise challenge test, like running on a treadmill, riding a stationary bike or climbing stairs, in order to trigger symptoms. The exercise challenge ends with another spirometry test, which will reveal any changes in lung function.