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The Ewha Medical Journal
Ewha Womans University School of Medicine

Ewha Med J 1998; 21(2):73-79

pISSN: 1598-7450

DOI: https://doi.org/10.12771/emj.1998.21.2.73

Original Article

The Nonspecific Bronchial Hyper-reactivity during Refractory Period Following Exercise in Exercise-Induced Asthma

Young Joo Cho

Copyright ⓒ 1998. Ewha Womans University School of Medicine. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Published Online: Jun 30, 1998

Abstract

Objectives

In order to elucidate the important factors for refractoriness following repeated exercise in exercise-induced asthma(EIA), we investigated the relationship between the change of bronchial hyper-reactivity to methacholine during the refractory period and the degree of refractoriness following the exercise.

Methods

Ten EIA patients were tested. First visit included methacholine bronchial provo-cation test(MBPT) followed by exercise 1 and repeated MBPT separated by a 60 min. On seco-nd visit, exercise 3 were repeated after 60 min of exercise 2, and refractoriness was measured.

Results

The maximal broncial constriction measured by FEV1 was 22.6±4.2% and this reaction was recovered over 95% within 60 min. Methacholine PC20(PC20M) was decreased after exercise in six from 10 EIA patients. There was no significant relationship between the degree of exercise induced bronchial-constriction and the chagne of PC20 after exercise. The bronchial hyper-reactivity to methacholine was in--creased after exercise even with the refracto-riness in some of EIA patients.

Conclusion

Refractoriness followed by repeated exercise does not seem to be due to the decreased bronchial hyper-reactivity.