Document Detail

Influence of global inspiratory muscle fatigue on breathing during exercise.
MedLine Citation:
PMID:  8926256     Owner:  NLM     Status:  MEDLINE    
We evaluated the effect of global inspiratory muscle fatigue (GF) on respiratory muscle control during exercise at 30, 60, and 90% of maximal power output in normal subjects. Fatigue was induced by breathing against a high inspiratory resistance until exhaustion. Esophageal and gastric pressures, anteroposterior displacement of the rib cage and abdomen, breathing pattern, and perceived breathlessness were measured. Induction of GF had no effect on the ventilatory parameters during mild and moderate exercise. It altered, however, ventilatory response to heavy exercise by increasing breathing frequency and minute ventilation, with minor changes in tidal volume. This was accompanied by an increase in perceived breathlessness. GF significantly increased both the tonic and phasic activities of abdominal muscles that allowed 1) the diaphragm to maintain its function while developing less pressure, 2) the same tidal volume with lesser shortening of the rib cage inspiratory muscles, and 3) relaxation of the abdominal muscles to contribute to lung inflation. The increased work performed by the abdominal muscles may, however, lead to a reduction in their strength. GF may impair exercise performance in some healthy subjects that is probably not related to excessive breathlessness or other ventilatory factors. We conclude that the respiratory system is remarkably adaptable in maintaining ventilation during exercise even with impaired inspiratory muscle contractility.
P Sliwiński; S Yan; A P Gauthier; P T Macklem
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  80     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1996 Apr 
Date Detail:
Created Date:  1996-11-27     Completed Date:  1996-11-27     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1270-8     Citation Subset:  IM; S    
Meakins-Christie Laboratories, McGill University Clinic, Royal Victoria Hospital, Montreal, Quebec, Canada.
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MeSH Terms
Exercise / physiology*
Leg / physiology
Muscle Fatigue / physiology*
Pulmonary Ventilation / physiology*
Respiration / physiology*

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

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