Document Detail

Bronchoconstriction during cross-country skiing: is there really a refractory period?
MedLine Citation:
PMID:  12544630     Owner:  NLM     Status:  MEDLINE    
PURPOSE: The asthmatic airway responds to exercise by bronchodilation (BD) during and bronchoconstriction (BC) after exercise. A refractory period induced by an initial exercise challenge that provides protection against BC during a subsequent exercise bout has also been observed. However, no studies examining during-exercise response or refractoriness during long-duration field exercise by elite athletes have been performed. This study examined airway response and refractoriness during approximately 42-min cross-country ski time trial preceded by a 6- to 9-min 2.5-km high-intensity warm-up ski. METHODS: Eighteen elite athletes cross-country skied seven successive 2.5-km loops. Spirometry was performed pre- and at 5, 10, and 15 min post loop 1; loops 2-7 were treated as a race (XCR) with maneuvers performed within 20 s after loops 2-6 and serially for 15 min after lap 7. RESULTS: Nine of 18 subjects demonstrated a >or=10% fall from baseline in FEV(1) (EIB+): five after lap 1 and four during or after laps 2-7. FEV(1) for EIB+ athletes during XCR was not different from post lap 1 FEV. Only one EIB+ subject demonstrated significant refractoriness. Four EIB+ athletes had a less than 10% fall in FEV after the initial 2.5-km exercise challenge but developed EIB (>or=10% fall) during the subsequent 6 x 2.5 km XCR exercise challenge. FEF(25-75) falls mirrored FEV(1), but demonstrated greater BD during XCR. CONCLUSION: Bronchoconstriction occurs in athletes during prolonged exercise and may thus influence performance. Variability in bronchial hyperresponsiveness onset and the lack of significant refractoriness in our study cohort of athletes is consistent with an exercise bronchoconstrictive dysfunction that is different than frank asthma and is yet to be clearly defined.
Kenneth W Rundell; Barry A Spiering; Daniel A Judelson; Meredith H Wilson
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  35     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2003 Jan 
Date Detail:
Created Date:  2003-01-24     Completed Date:  2003-04-15     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  18-26     Citation Subset:  IM; S    
Marywood University, Scranton, PA 18509-4742, USA.
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MeSH Terms
Asthma, Exercise-Induced / physiopathology*
Bronchial Hyperreactivity / physiopathology*
Respiratory Function Tests
Skiing / physiology*

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

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