Document Detail

Influence of body position and pre-exercise activity on cardiac output and oxygen uptake following step changes in exercise intensity.
MedLine Citation:
PMID:  1483437     Owner:  NLM     Status:  MEDLINE    
Parallel measurements of breath-by-breath oxygen uptake, cardiac output (Doppler technique), blood pressure (Finapres technique) and heart rate were performed in nine subjects during cycle ergometer exercise in the upright and supine positions. Transients were monitored during power steps starting from and leading to either rest or lower levels of exercise intensity. Oxygen uptake (VO2) and cardiac output kinetics were markedly faster than in all other conditions when exercise was started from rest. In contrast to exercise-exercise on steps, the computed arteriovenous difference in O2 content increased almost immediately in this situation, indicating that not only the additional energy expenditure due to the acceleration of the flywheel but also an increased venous admixture from non-exercising parts of the body contributed to the early kinetics. The off kinetics generally showed a more uniform pattern and did not simply mirror the on transients. The present findings indicate that transitions from rest should be avoided when muscle VO2 kinetics are to be assessed on the basis of VO2 measurements at the mouth.
D Leyk; D Essfeld; U Hoffmann; K Baum; J Stegemann
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of applied physiology and occupational physiology     Volume:  65     ISSN:  0301-5548     ISO Abbreviation:  Eur J Appl Physiol Occup Physiol     Publication Date:  1992  
Date Detail:
Created Date:  1993-02-16     Completed Date:  1993-02-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0410266     Medline TA:  Eur J Appl Physiol Occup Physiol     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  499-506     Citation Subset:  IM; S    
Physiologisches Institut der Deutschen Sporthochschule Köln, Federal Republic of Germany.
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MeSH Terms
Blood Circulation / physiology
Blood Pressure / physiology
Cardiac Output / physiology*
Exercise / physiology*
Heart Rate / physiology
Oxygen / blood
Oxygen Consumption / physiology*
Posture / physiology*
Reg. No./Substance:

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