Document Detail


The effects of breathing a helium-oxygen gas mixture on maximal pulmonary ventilation and maximal oxygen consumption during exercise in acute moderate hypobaric hypoxia.
MedLine Citation:
PMID:  20623231     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To test the hypothesis that maximal exercise pulmonary ventilation (VE max) is a limiting factor affecting maximal oxygen uptake (VO2 max) in moderate hypobaric hypoxia (H), we examined the effect of breathing a helium-oxygen gas mixture (He-O(2); 20.9% O(2)), which would reduce air density and would be expected to increase VE max. Fourteen healthy young male subjects performed incremental treadmill running tests to exhaustion in normobaric normoxia (N; sea level) and in H (atmospheric pressure equivalent to 2,500 m above sea level). These exercise tests were carried out under three conditions [H with He-O(2), H with normal air and N] in random order. VO2 max and arterial oxy-hemoglobin saturation (SaO(2)) were, respectively, 15.2, 7.5 and 4.0% higher (all p < 0.05) with He-O(2) than with normal air (VE max, 171.9 ± 16.1 vs. 150.1 ± 16.9 L/min; VO2 max, 52.50 ± 9.13 vs. 48.72 ± 5.35 mL/kg/min; arterial oxyhemoglobin saturation (SaO(2)), 79 ± 3 vs. 76 ± 3%). There was a linear relationship between the increment in VE max and the increment in VO2 max in H (r = 0.77; p < 0.05). When subjects were divided into two groups based on their VO2 max, both groups showed increased VE max and SaO(2) in H with He-O(2), but VO2 max was increased only in the high VO2 max group. These findings suggest that in acute moderate hypobaric hypoxia, air-flow resistance can be a limiting factor affecting VE max; consequently, VO2 max is limited in part by VE max especially in subjects with high VO2 max.
Authors:
Takeshi Ogawa; Jose A L Calbet; Yasushi Honda; Naoto Fujii; Takeshi Nishiyasu
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-07-10
Journal Detail:
Title:  European journal of applied physiology     Volume:  110     ISSN:  1439-6327     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-10-20     Completed Date:  2010-12-10     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  853-61     Citation Subset:  IM    
Affiliation:
Institute of Health and Sports Science, University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan.
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MeSH Terms
Descriptor/Qualifier:
Abdomen, Acute
Adult
Altitude
Anoxia / physiopathology*
Atmospheric Pressure
Exercise / physiology*
Exercise Test
Helium*
Humans
Male
Models, Biological
Oxygen / blood*
Oxygen Consumption / physiology*
Oxyhemoglobins / metabolism
Pulmonary Ventilation / physiology*
Young Adult
Chemical
Reg. No./Substance:
0/Oxyhemoglobins; 7440-59-7/Helium; 7782-44-7/Oxygen

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


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