Airway obstruction often develops in children with asthma after physical exertion. This exerciseinduced bronchoconstriction on asthma is not limited to children with asthma but also occurs in children with allergic rhinitis without clinically necognizable asthma. Typically, 5 to 8 minutes of vigorous exercise is sufficient to make the child short of breath, and symptoms of coughing, chest tightness, and wheezing begin shortly afterward. Chest pain, shortness of breath, and/on chest tightness may be the only complaints. Usually, within ½ to 1 hour, the episode subsides spontaneously. Some children appear to also have a delayed (4 to 12 hours) response to exercise, with the same symptoms that were present immediately after exercise.
The severity of such an attack of exercise-induced asthma depends on many factors. Children with poorly controlled asthma may have increased airway obstruction with trivial exercise such as walking or climbing a flight of stairs. The severity of obstruction at the onset of exercise may contribute as well, because an attack that begins with partially obstructed airways may end with more obstructed airways. The cold, dry ambient air significantly increases obstruction, as do many industrial pollutants, particularly sulfur dioxide. Both reactivity and obstruction may worsen with or after a viral infection on with allergen exposure, so that an asthmatic child's response to exercise may vary dramatically from day to day.
The exercise itself is an important variable but is individualized. Strenuous exercise increases the severity of the asthma and a short, intense effort may induce exercise-induced asthma as well as a longer, less intense effort.
- Copyright © 1989 by the American Academy of Pediatrics