The observation that different forms of exercise can induce varying degrees of bronchoconstriction in asthmatic patients remains to be explained. The aim of this study was to determine whether the degree of bronchoconstriction is dependent on the level of hyperpnea as recorded during different forms of exercise. 9 asthmatics (10–16 years of age) performed treadmill walking, arm peddling and leg cycling on 3 separate days. On the 4 study day, all patients performed voluntary hyperpnea under isocapnic conditions. Each challenge, i.e. exercise and/or hyperpnea, lasted 10 min. The subject breathed room (19–23 °C, 7–14% relative humidity) air through the mouth. The following variables were continously monitored: ventilation (VE), end-tidal and mixed expiratory Pco2 and heart rate. The pulmonary functions measured before and at 7–15 min after challenge included spiro < metry, MEFV curve and SGaw. It was found that: (1) all four forms of challenges when matched for minute ventilation (a mean of 42.3 ± 0.2 liters/min) induced a comparable degree of bronchoconstriction. This was measured by all pulmonary function variables including Vmax at 70% TLC and SGaw. The voluntary isocapnic hyperpnea is an equally strong stimulus to bronchospasm when compared to absolute exercise hyperpnea, regardless of the method of exercise. (2) Both ventilatory response and oxygen consumption measured during leg cycling were significantly increased in asthmatics when compared to normal range. (3) Each individual showed a dose-response-like relationship between minute ventilation measured during exercise and the degree of bronchoconstriction following this challenge, as measured by pulmonary functions.

Keywords:
Hyperpnea, Exercise, Airway hyperreactivity
This content is only available via PDF.
© 1980 S. Karger AG, Basel
1980
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.