Is asthma over- or under-diagnosed in athletes?

A high prevalence of asthma has been reported in athletes. However, studies in this population usually show an even higher prevalence of airway hyperresponsiveness (AHR) and exercise-induced bronchoconstriction (EIB). This report compares studies on self-reported or physician-diagnosed asthma in athletes with those using objective measures of airflow limitation or airway responsiveness. The higher prevalence of AHR (or EIB) measured in athletes, when compared with the prevalence of self-reported or physician-diagnosed asthma, suggests that abnormal airway responses are common in athletes, although they are infrequently associated with troublesome respiratory symptoms. This may indicate underdiagnosis of asthma in athletes, possibly due to an underreporting of respiratory symptoms or a reduction in perception of nociceptive sensations with repeated exercise over time, or it may simply mean that high-level training is associated with asymptomatic AHR. In athletes, as in the general population, the use of subjective methods such as surveys and questionnaires results in an underestimation ofthe prevalence of airway dysfunction when compared with objective measurements. The significance of these observations is unknown, and there is a need to determine their long-term consequences for athletes.