Document Detail

Fluid-regulatory hormone responses during cycling exercise in acute hypobaric hypoxia.
MedLine Citation:
PMID:  15595294     Owner:  NLM     Status:  MEDLINE    
PURPOSE: This study was designed to describe the responses of fluid-regulating hormones during exercise in acute hypobaric hypoxia and to test the hypothesis that they would be dependent on the relative intensity of exercise rather than the absolute workload. METHODS: Thirteen men cycled for 60 min on four occasions in the same individual hydration status: in normoxia at 55% and 75% of normoxia maximal aerobic power (N55 and N75, respectively), in hypoxia (PB = 594 hPa) at the same absolute workload and at the same relative intensity as N55 (H75 and H55, respectively). VO2, heart rate, and rectal and mean skin temperatures were recorded during exercise. The total water loss was measured by the difference in nude body mass adjusted for metabolic losses. Venous blood samples were drawn before and 15, 30, 45, and 60 min after the beginning of exercise to measure variations in plasma volume, osmolality, and concentrations in arginine vasopressin (AVP), atrial natriuretic factor (ANF), plasma renin activity (ARP), aldosterone (Aldo), and noradrenaline (NA). RESULTS: During N55 and H55, AVP, Aldo and ARP did not change, whereas ANF increased slightly. Increases in AVP, Aldo, ARP, and NA were greater during N75 than during H75, whereas the increase in ANF was greater during H75 than N75. CONCLUSION: Plasma levels of AVP, Aldo, and ARP increase during exercise when a threshold is reached and thereafter are dependent on the absolute workload, without any specific effect of hypoxia. The time course of ANF appears to be different from that of the other hormones.
Olivier Bocqueraz; Nathalie Koulmann; Bruno Guigas; Chantal Jimenez; Bruno Melin
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Publication Detail:
Type:  Clinical Trial; Journal Article    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  36     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2004 Oct 
Date Detail:
Created Date:  2004-12-14     Completed Date:  2005-02-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1730-6     Citation Subset:  IM; S    
Department of Human Factors, National Health Research Center for Defense, CRSSA, La Tronche, France.
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MeSH Terms
Aldosterone / blood
Anoxia / blood*,  physiopathology
Arginine Vasopressin / blood
Atrial Natriuretic Factor / blood
Body Temperature / physiology
Exercise Test*
Heart Rate / physiology
Norepinephrine / blood
Osmolar Concentration
Oxygen / blood
Oxygen Consumption / physiology
Plasma Volume / physiology
Renin / blood
Sweat / metabolism
Reg. No./Substance:
113-79-1/Arginine Vasopressin; 51-41-2/Norepinephrine; 52-39-1/Aldosterone; 7782-44-7/Oxygen; 85637-73-6/Atrial Natriuretic Factor; EC

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