Document Detail

Refractory period after exercise-induced asthma unexplained by respiratory heat loss.
MedLine Citation:
PMID:  6177268     Owner:  NLM     Status:  MEDLINE    
Fifteen asthmatic children and young adults each exercised for 6 min by cycling on a cycle ergometer while breathing either cold (4.1 degrees C +/- 0.5 SEM) and dry (2.05 mg/L +/- 0.05) air or warm (37.2 degrees C +/- 0.3) fully saturated air. Each subject performed 4 tests arranged in pairs. Test pair A consisted of cold dry exercise followed by another cold dry exercise and test pair B consisted of a warm humid exercise followed by a cold dry exercise. Ventilation, heart rate, and gas exchange were closely matched in all 4 tests in each subject with a mean oxygen consumption of 34.8 +/- 0.8 ml/min/kg. In test pair A, all subjects were rendered refractory by the first cold dry exercise as manifested by a significant attenuation of their exercise-induced asthma (EIA) after the second cold dry test (per cent decrease in FEV1, delta FEV1 = 16 +/- 4 compared with 38 +/- 4). In 3 subjects, the warm humid exercise did not cause EIA and did not render them refractory to the second cold dry exercise. The 12 remaining subjects exhibited a refractory period similar to that shown in test pair A. They did not develop EIA after the warm humid test (delta FEV1 = 1 +/- 2), but after the subsequent cold dry exercise the per cent decrease in FEV1 was 19 +/- 3, similar to that in the second of the 2 cold dry exercise tests. These experiments suggest that in the majority of subjects exercise per se appears to be the cause for refractoriness and not airway cooling or bronchoconstriction.
I Ben-Dov; E Bar-Yishay; S Godfrey
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The American review of respiratory disease     Volume:  125     ISSN:  0003-0805     ISO Abbreviation:  Am. Rev. Respir. Dis.     Publication Date:  1982 May 
Date Detail:
Created Date:  1982-07-19     Completed Date:  1982-07-19     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0370523     Medline TA:  Am Rev Respir Dis     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  530-4     Citation Subset:  AIM; IM    
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MeSH Terms
Asthma / physiopathology*
Asthma, Exercise-Induced / physiopathology*
Body Temperature Regulation*
Forced Expiratory Volume
Histamine Release
Time Factors
Vagus Nerve / physiopathology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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