Document Detail

Independence of exercise-induced diaphragmatic fatigue from ventilatory demands.
MedLine Citation:
PMID:  18166504     Owner:  NLM     Status:  MEDLINE    
Exercise-induced diaphragmatic fatigue (DF) manifests after - rather than during - exercise. This suggests that DF reflects post-exercise diaphragm-shielding. This study tested the physiological hypothesis that diaphragmatic force-generation undergoes similar regulations during either whole-body-exercise or controlled hyperventilation, but differs during recovery. Ten trained subjects (VO2(max) 60.3+/-6.4 ml/kg/min) performed: I, cycling exercise (maximal workload: 85% VO2(max)); II, controlled hyperventilation (exercise breathing pattern) followed by recovery. Ergospirometric data and twitch transdiaphragmatic pressure (TwPdi) were consecutively assessed. DF occurred following exercise, while hyperventilation enhanced diaphragmatic force-generation (TwPdi-rest 2.28+/-0.58 vs. 2.52+/-0.54, TwPdi-end-recovery: 1.94+/-0.32 kPa vs. 2.81+/-0.49 kPa, both p<0.05). TwPdi was comparable between the two protocols until recovery (p>0.05, RM-ANOVA) whereby it underwent a progressive increase. In conclusion, TwPdi progressively increases and is subject to similar regulations during exercise versus controlled hyperventilation, but differs markedly during recovery. Here, DF occurred after exercise while TwPdi increased subsequent to hyperventilation. Therefore, ventilatory demands regulate diaphragmatic force-generation during exercise, whereas DF must be attributed to non-ventilatory controlled feedback mechanisms.
Hans-Joachim Kabitz; David Walker; Stephan Walterspacher; Florian Sonntag; Anja Schwoerer; Kai Roecker; Wolfram Windisch
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Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2007-11-28
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  161     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2008 Apr 
Date Detail:
Created Date:  2008-04-28     Completed Date:  2008-07-25     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  101-7; discussion 108-10     Citation Subset:  IM    
Department of Pneumology, University Hospital Freiburg, Killianstrasse 5, D-79106 Freiburg, Germany.
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MeSH Terms
Analysis of Variance
Diaphragm / physiology*
Exercise Test
Hyperventilation / physiopathology*
Muscle Contraction / physiology
Muscle Fatigue / physiology*
Muscle Strength / physiology*
Oxygen Consumption / physiology
Physical Exertion / physiology*
Pulmonary Ventilation / physiology*
Recovery of Function / physiology
Reference Values
Statistics, Nonparametric

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

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