Prevalence of exercise induced asthma in female school students.

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.