Document Detail

Factors determining the time course of VO2(max) decay during bedrest: implications for VO2(max) limitation.
MedLine Citation:
PMID:  16924528     Owner:  NLM     Status:  MEDLINE    
The aim of this study was to characterize the time course of maximal oxygen consumption VO2(max) changes during bedrests longer than 30 days, on the hypothesis that the decrease in VO2(max) tends to asymptote. On a total of 26 subjects who participated in one of three bedrest campaigns without countermeasures, lasting 14, 42 and 90 days, respectively, VO2(max) maximal cardiac output (Qmax) and maximal systemic O2 delivery (QaO2max) were measured. After all periods of HDT, VO2max, Qmax, and QaO2max were significantly lower than before. The VO2max decreased less than qmax after the two shortest bedrests, but its per cent decay was about 10% larger than that of Qmax after 90-day bedrest. The VO2max decrease after 90-day bedrest was larger than after 42- and 14-day bedrests, where it was similar. The Qmax and QaO2max declines after 90-day bedrest was equal to those after 14- and 42-day bedrest. The average daily rates of the VO2max, Qmax, and QaO2max decay during bedrest were less if the bedrest duration were longer, with the exception of that of VO2max in the longest bedrest. The asymptotic VO2max decay demonstrates the possibility that humans could keep working effectively even after an extremely long time in microgravity. Two components in the VO2max decrease were identified, which we postulate were related to cardiovascular deconditioning and to impairment of peripheral gas exchanges due to a possible muscle function deterioration.
C Capelli; G Antonutto; M Azabji Kenfack; M Cautero; F Lador; C Moia; E Tam; G Ferretti
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Publication Detail:
Type:  Controlled Clinical Trial; Journal Article     Date:  2006-08-19
Journal Detail:
Title:  European journal of applied physiology     Volume:  98     ISSN:  1439-6319     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2006 Sep 
Date Detail:
Created Date:  2006-09-07     Completed Date:  2006-11-20     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  152-60     Citation Subset:  IM    
Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, Udine, Italy.
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MeSH Terms
Adaptation, Physiological / physiology
Bed Rest*
Exercise Test
Oxygen Consumption / physiology*
Physical Endurance / physiology*
Physical Exertion / physiology*
Rest / physiology*

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