Exercise-induced asthma in asthmatic children of southern Iran

Asthma is a common illness, especially among children. Exercise-induced asthma is an important consideration, both as a factor, limiting physical activity of patients, and also as an indicator of poor long term control. We investigated pre-Valence of exercise-induced asthma in a group of asthmatic children living in southern Iran.

We conducted treadmill exercise challenge test in 40 young asthmatic patients aged 6 to 18. After 8 minutes exercise to achieve 80% of maximum heart rate predicted for age, patients were examined and spirometry values recorded at frequent intervals. We defined exercise-induced asthma as 10% or more decline in Forced Expiratory Volume in one second (FEV1) within 30 minutes after exercise challenge.

Of 40 patients evaluated, 22 patients ( 55% of total ) met our criteria for exercise-induced asthma. Most positive responses (7 of 22, 31.8%) occurred at about 10 minutes after exercise. Cough was the most consistent sign (18 of 22 patients, 81%). In 2 patients (9%), FEV 1 decline did not accompany any symptom or sign.

We concluded that Exercise- induced asthma occurs in a relatively smaller subset of southern Iranian asthmatic children. Also treadmill exercise challenge performed by a trained staff, following standard protocol and using enough monitoring and precautions is safe and diagnostic in children and adolescents.