Document Detail


Determinants of exercise performance in normal men with externally imposed expiratory flow limitation.
MedLine Citation:
PMID:  11960944     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To understand how externally applied expiratory flow limitation (EFL) leads to impaired exercise performance and dyspnea, we studied six healthy males during control incremental exercise to exhaustion (C) and with EFL at approximately 1. We measured volume at the mouth (Vm), esophageal, gastric and transdiaphragmatic (Pdi) pressures, maximal exercise power (W(max)) and the difference (Delta) in Borg scale ratings of breathlessness between C and EFL exercise. Optoelectronic plethysmography measured chest wall and lung volume (VL). From Campbell diagrams, we measured alveolar (PA) and expiratory muscle (Pmus) pressures, and from Pdi and abdominal motion, an index of diaphragmatic power (W(di)). Four subjects hyperinflated and two did not. EFL limited performance equally to 65% W(max) with Borg = 9-10 in both. At EFL W(max), inspiratory time (TI) was 0.66s +/- 0.08, expiratory time (TE) 2.12 +/- 0.26 s, Pmus approximately 40 cmH2O and DeltaVL-DeltaVm = 488.7 +/- 74.1 ml. From PA and VL, we calculated compressed gas volume (VC) = 163.0 +/- 4.6 ml. The difference, DeltaVL-DeltaVm-VC (estimated blood volume shift) was 326 ml +/- 66 or 7.2 ml/cmH2O PA. The high Pmus and long TE mimicked a Valsalva maneuver from which the short TI did not allow recovery. Multiple stepwise linear regression revealed that the difference between C and EFL Pmus accounted for 70.3% of the variance in DeltaBorg. DeltaW(di) added 12.5%. We conclude that high expiratory pressures cause severe dyspnea and the possibility of adverse circulatory events, both of which would impair exercise performance.
Authors:
Iacopo Iandelli; Andrea Aliverti; Bengt Kayser; Raffaele Dellacà; Stephen J Cala; Roberto Duranti; Susan Kelly; Giorgio Scano; Pawel Sliwinski; Sheng Yan; Peter T Macklem; Antonio Pedotti
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  92     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2002 May 
Date Detail:
Created Date:  2002-04-18     Completed Date:  2002-06-21     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:  1943-52     Citation Subset:  IM    
Affiliation:
Fondazione Don Gnocchi, I-50020 Pozzolatico, Italy.
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MeSH Terms
Descriptor/Qualifier:
Adult
Blood Volume / physiology
Diaphragm / physiology
Exercise Test
Exercise Tolerance / physiology*
Forced Expiratory Flow Rates / physiology*
Humans
Inspiratory Capacity / physiology*
Male
Physical Exertion / physiology
Plethysmography
Pressure
Pulmonary Ventilation / physiology*
Reference Values
Total Lung Capacity / physiology

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


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