Document Detail

Effects of acute hypoxia on the estimation of lactate threshold from ventilatory gas exchange indices during an incremental exercise test.
MedLine Citation:
PMID:  15588134     Owner:  NLM     Status:  MEDLINE    
The purpose of this study was to investigate the validity of non-invasive lactate threshold estimation using ventilatory and pulmonary gas exchange indices under condition of acute hypoxia. Seven untrained males (21.4+/-1.2 years) performed two incremental exercise tests using an electromagnetically braked cycle ergometer: one breathing room air and other breathing 12 % O2. The lactate threshold was estimated using the following parameters: increase of ventilatory equivalent for O2 (VE/VO2) without increase of ventilatory equivalent for CO2 (VE/VCO2). It was also determined from the increase in blood lactate and decrease in standard bicarbonate. The VE/VO2 and lactate increase methods yielded the respective values for lactate threshold: 1.91+/-0.10 l/min (for the VE/VO2) vs. 1.89+/-0.1 l/min (for the lactate). However, in hypoxic condition, VE/VO2 started to increase prior to the actual threshold as determined from blood lactate response: 1.67+/-0.1 l/min (for the lactate) vs. 1.37+/-0.09 l/min (for the VE/VO2) (P=0.0001), i.e. resulted in pseudo-threshold behavior. In conclusion, the ventilatory and gas exchange indices provide an accurate lactate threshold. Although the potential for pseudo-threshold behavior of the standard ventilatory and gas exchange indices of the lactate threshold must be concerned if an incremental test is performed under hypoxic conditions in which carotid body chemosensitivity is increased.
O Ozcelik; H Kelestimur
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Validation Studies    
Journal Detail:
Title:  Physiological research / Academia Scientiarum Bohemoslovaca     Volume:  53     ISSN:  0862-8408     ISO Abbreviation:  Physiol Res     Publication Date:  2004  
Date Detail:
Created Date:  2004-12-13     Completed Date:  2005-05-31     Revised Date:  2008-04-02    
Medline Journal Info:
Nlm Unique ID:  9112413     Medline TA:  Physiol Res     Country:  Czech Republic    
Other Details:
Languages:  eng     Pagination:  653-9     Citation Subset:  IM    
Department of Physiology, Firat University, Faculty of Medicine, Elazig, Turkey.
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MeSH Terms
Acute Disease
Anaerobic Threshold*
Anoxia / physiopathology*
Exercise Test / methods*
Lactic Acid / blood*
Oxygen Consumption*
Pulmonary Gas Exchange*
Reproducibility of Results
Sensitivity and Specificity
Statistics as Topic
Reg. No./Substance:
50-21-5/Lactic Acid

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

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