RESUMEN
The prevalence of exercise induced asthma [EIA] in Iran is not known. In the present study the prevalence of EIA among female students of guidance school in the city of Mashhad was evaluated. A total of 1690 female students aged 12-14 years in ten randomly selected schools in north east of Iran [Mashhad] completed an asthma symptoms- specific questionnaire. One hundred forty four randomly selected students including 49 symptomatic and 95 asymptomatic cases participated in a 6 minutes free run test [until reaching 70-75% of MHR [maximum heart rate] for evaluating EIA. Pulmonary function tests [PFT] were measured, before [baseline], immediately, 5 minutes and 15 minutes after exercise. The prevalence of asthma symptoms among the studied students was 12.54%. There was not significant difference in any of PFT values between asymptomatic and symptomatic students. The results of exercise test showed that totally 61.22% of symptomatic students responded to exercise test [their post-exercise PFT values decline more than 15%] while only 16.82% of asymptomatic students were responders to exercise [p<0.001]. However, in both asymptomatic and symptomatic responder students, all PFT values declined significantly after exercise compared to baseline values [p<0.05 to p<0.001] and there was not any significant difference between two groups. The results showed that although higher number of symptomatic students showed EIA, some asymptomatic students also sowed EIA