Exercise-induced bronchospasm in a hot and dry region: study of asthmatic, rhinitistic and asymptomatic adolescents.

BACKGROUND: Exercise-induced bronchospasm (EIB) is the bronchial narrowing that occurs after intense exercise in a significant number of asthmatics and in some non-asthmatics. This study aims to evaluate the occurrence of EIB in adolescents with asthma, rhinitis and respiratory asymptomatics in a hot and dry climate.

RESEARCH DESIGN AND METHODS: This is a cross-sectional study based on an epidemiological study that evaluated the prevalence of asthma in schoolchildren in a semi-arid zone of Brazil. The EIB was defined as a reduction in forced expiratory volume in first second (FEV1 ) greater than 10%.

RESULTS: A total of 114 individuals participated in the study (36.8% male), of whom 54 were asymptomatic, 30 asthmatic and 30 with rhinitis. Asthmatics presented a higher proportion of EIB in comparison to rhinitis and asymptomatics (46.7% vs. 13.3% and 7.4%, p = 0.001) and none of the individuals had severe EIB (ΔFEV1  ≥ 50%).

CONCLUSIONS: A large proportion of the asthmatics selected from the community for the clinical study had EIB. Among participants with rhinitis, EIB was found in slightly more than 10%, while in the asymptomatics the frequency was slightly more than 5%. This study presents an important aspect in individuals living in hot and dry climates.