Document Detail


Acute hypervolemia does not improve arterial oxygenation in maximally exercising thoroughbred horses.
MedLine Citation:
PMID:  15455236     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Recently, it was reported that acute hypervolemia improves arterial oxygen tension in human athletes known to experience exercise-induced arterial hypoxemia. Since exercise-induced arterial hypoxemia is routinely observed in racehorses and is known to limit performance, we examined whether pre-exercise induction of acute hypervolemia would similarly benefit arterial oxygenation in maximally exercising thoroughbred horses. Two sets of experiments, namely, placebo [intravenous (IV) physiological saline] and acute hypervolemia (IV 7.2% NaCl, causing an 18.2% expansion of plasma volume) studies were carried out in random order on 13 healthy, exercise-trained thoroughbred horses, 7 days apart. An incremental exercise protocol leading to 120 s of galloping at 14 m s(-1) on a 3.5% uphill incline was used. Galloping at this workload elicited maximal heart rate and induced pulmonary hemorrhage in all horses in both treatments. In the placebo study, arterial oxygen tension decreased to 76.1 (2) mmHg (P<0.0001) at 30 s of maximal exertion, but further significant changes did not occur as exercise duration increased to 120 s [arterial oxygen tension 72.4 (2) mmHg]. A significant arterial hypoxemia also developed in galloping horses in the acute hypervolemia study [arterial oxygen tension at 30 and 120 s was 76.7 (1.7) and 71.9 (1.6) mmHg, respectively], but significant differences between treatments could not be demonstrated. In both treatments, a similar desaturation of arterial hemoglobin was also observed at 30 s of maximal exercise, which intensified with increasing exercise duration as hyperthermia, acidosis and hypercapnia intensified. Thus, acute expansion of plasma volume did not benefit arterial oxygenation in maximally exercising thoroughbred horses.
Authors:
Murli Manohar; Thomas E Goetz; Aslam S Hassan
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2004-09-29
Journal Detail:
Title:  European journal of applied physiology     Volume:  93     ISSN:  1439-6319     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2005 Jan 
Date Detail:
Created Date:  2004-12-24     Completed Date:  2005-07-05     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  480-8     Citation Subset:  IM    
Affiliation:
212 Large Animal Clinic, Departments of Veterinary Biosciences and Clinical Medicine, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 1102 W. Hazelwood Drive, Urbana, IL 61801, USA. mmanohar@uiuc.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Arteries / drug effects,  physiology*
Blood Volume / drug effects,  physiology*
Female
Horses / blood*,  physiology*
Male
Oxygen / blood*
Oxygen Consumption / physiology*
Physical Endurance / drug effects,  physiology*
Physical Exertion / drug effects,  physiology*
Sodium Chloride / pharmacology
Chemical
Reg. No./Substance:
7647-14-5/Sodium Chloride; 7782-44-7/Oxygen

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


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