Having a bad day on the soccer field or treadmill? Maybe you can blame asthma—even if you don't have symptoms.
You might doubt that the athletic field would be a place to find asthmatics, but new research suggests that a significant proportion of college athletes have exercise-induced asthma, which often is silent and symptomless. Researchers say that recreational athletes, too, should be alert to signs of the condition, which can affect performance and in extreme cases be dangerous. According to a team at Ohio State University Medical Center that studied 107 varsity athletes representing 22 sports, 39 percent experienced the constricting of the airways during a workout, or bronchospasm, that is the hallmark of exercise-induced asthma. Of those athletes with the diagnosis, 86 percent had no previous history of asthma or bronchospasm.
How could athletes not know their airways are closing up? The constriction, caused by the large amounts of cool, drier air entering the lungs during exercise, often isn't severe enough to cause obvious symptoms like wheezing and chest tightness. And because it doesn't occur during their regular activity, many athletes with EIA don't think much of it. They just chalk up bad performances in races or workouts to being tired or out of shape.
EIA has been studied mostly in top athletes, of whom 10 percent to 50 percent appear to be affected, depending on the sport. (Winter Olympics athletes seem more vulnerable than summer Olympics athletes, probably because of the colder air; athletes who work out or compete in ice rinks may be especially susceptible because of air pollution from the resurfacing machines.) But while it may be more obvious in athletes who are pushing their bodies to the limit, people working out recreationally should be cognizant of the risk as well, says John Weiler, a longtime asthma researcher and an author of this year's American Academy of Allergy, Asthma and Immunology work group report on the condition.
Weiler once tested a football player by having him run up flights of stairs in the hospital; the athlete was asthma free, but the allergist-in-training who accompanied the player turned out to have it. Jonathan Parsons, associate director of Ohio State Medical Center's Asthma Center and lead author of the study, says previous research found that about 20 percent of people working out in a fitness center had the condition. Parsons says that if you are working out regularly but are inexplicably tired or don't see fitness or performance gains in proportion to the time you spend training—you're running more than ever but your 5k time hasn't budged—you should see an allergist or pulmonologist.
The good news is that silent EIA isn't likely to kill, though in rare cases it can shut down the airways entirely. The performance lag, whether in elites or recreational athletes, can often be treated by taking special measures—like a longer warm-up—or with an albuterol inhaler.