Document Detail

Intense hypoxic cycle exercise does not alter lung density in competitive male cyclists.
MedLine Citation:
PMID:  17219166     Owner:  NLM     Status:  MEDLINE    
We tested the hypothesis that intense short duration hypoxic exercise would result in an increase in extravascular lung water (EVLW), as evidenced by an increase in lung density. Using computed tomography (CT), baseline lung density was obtained in eight highly trained male cyclists (mean +/- SD: age = 28 +/- 8 years; height = 180 +/- 9 cm; mass = 71.6 +/- 8.2 kg; VO2max= 65.0 +/- 5.2 ml kg min(-1)). Subjects then completed an intense hypoxic exercise challenge on a cycle ergometer and metabolic data, HR and %S(p)O2 were recorded throughout. While breathing 15% O2, subjects performed five 3 km cycling intervals (mean power, 286 +/- 20 W; HR = 91 +/- 4% HRmax) separated by 5 min of recovery. From a resting hypoxic S(p)O2 of 92 +/- 4%, subjects further desaturated during exercise to 76 +/- 3%. CT scans were repeated 76 +/- 10 min (range 63-88 min) following the completion of exercise. There was no change in lung density from pre (0.18 +/- 0.02 g ml(-1)) to post-exercise (0.18 +/- 0.04 g ml(-1)). The substantial reduction in S(p)O2 may be explained by a number of potential mechanisms, including decreased pulmonary diffusion capacity, alveolar hypoventilation, reduced red cell transit time, ventilation/perfusion inequality or a temperature and pH induced rightward-shift in the oxyhaemoglobin dissociation curve. Alternatively, the integrity of the blood gas barrier may have been disrupted without any measurable increase in lung density.
M J MacNutt; J A Guenette; J D Witt; R Yuan; J R Mayo; D C McKenzie
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Publication Detail:
Type:  Journal Article     Date:  2007-01-12
Journal Detail:
Title:  European journal of applied physiology     Volume:  99     ISSN:  1439-6319     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2007 Apr 
Date Detail:
Created Date:  2007-03-08     Completed Date:  2007-05-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  623-31     Citation Subset:  IM    
School of Human Kinetics, University of British Columbia, Vancouver, Canada.
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MeSH Terms
Anaerobic Threshold / physiology
Anoxia / metabolism*
Bicycling / physiology*
Blood Pressure / physiology
Body Water / metabolism,  physiology
Exercise / physiology*
Extravascular Lung Water / physiology
Heart Rate / physiology
Lung / physiology*
Physical Fitness / physiology*
Pulmonary Artery / physiology
Respiratory Mechanics / physiology
Tomography, X-Ray Computed
Vasoconstriction / physiology

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