Document Detail

The effect of breathing an ambient low-density, hyperoxic gas on the perceived effort of breathing and maximal performance of exercise in well-trained athletes.
MedLine Citation:
PMID:  17062658     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The role of the perception of breathing effort in the regulation of performance of maximal exercise remains unclear.
AIMS: To determine whether the perceived effort of ventilation is altered through substituting a less dense gas for normal ambient air and whether this substitution affects performance of maximal incremental exercise in trained athletes.
METHODS: Eight highly trained cyclists (mean SD) maximal oxygen consumption (VO(2)max) = 69.9 (7.9) (mlO(2)/kg/min) performed two randomised maximal tests in a hyperbaric chamber breathing ambient air composed of either 35% O(2)/65% N(2) (nitrox) or 35% O(2)/65% He (heliox). A ramp protocol was used in which power output was incremented at 0.5 W/s. The trials were separated by at least 48 h. The perceived effort of breathing was obtained via Borg Category Ratio Scales at 3-min intervals and at fatigue. Oxygen consumption (VO(2)) and minute ventilation (V(E)) were monitored continuously.
RESULTS: Breathing heliox did not change the sensation of dyspnoea: there were no differences between trials for the Borg scales at any time point. Exercise performance was not different between the nitrox and heliox trials (peak power output = 451 (58) and 453 (56) W), nor was VO(2)max (4.96 (0.61) and 4.88 (0.65) l/min) or maximal V(E) (157 (24) and 163 (22) l/min). Between-trial variability in peak power output was less than either VO(2)max or maximal V(E).
CONCLUSION: Breathing a less dense gas does not improve maximal performance of exercise or reduce the perception of breathing effort in highly trained athletes, although an attenuated submaximal tidal volume and V(E) with a concomitant reduction in VO(2) suggests an improved gas exchange and reduced O(2) cost of ventilation when breathing heliox.
L Ansley; D Petersen; A Thomas; A St Clair Gibson; P Robson-Ansley; T D Noakes
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2006-10-24
Journal Detail:
Title:  British journal of sports medicine     Volume:  41     ISSN:  1473-0480     ISO Abbreviation:  Br J Sports Med     Publication Date:  2007 Jan 
Date Detail:
Created Date:  2006-12-22     Completed Date:  2007-03-19     Revised Date:  2013-06-07    
Medline Journal Info:
Nlm Unique ID:  0432520     Medline TA:  Br J Sports Med     Country:  England    
Other Details:
Languages:  eng     Pagination:  2-7     Citation Subset:  IM    
School of Life Sciences, Kingston University, Penrhyn Road, Kingston-upon-Thames, Surrey KT1 2EE, UK.
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MeSH Terms
Anaerobic Threshold / physiology
Analysis of Variance
Bicycling / physiology*
Exercise Test / methods
Helium / administration & dosage*
Nitrogen / administration & dosage*
Oxygen / administration & dosage*
Oxygen Consumption / physiology*
Pulmonary Gas Exchange / physiology
Single-Blind Method
Reg. No./Substance:
37291-87-5/nitrox; 58933-55-4/heliox; 7440-59-7/Helium; 7727-37-9/Nitrogen; 7782-44-7/Oxygen

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

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