Document Detail


Dynamics of ventilation, circulation, and gas exchange to incremental and decremental ramp exercise.
MedLine Citation:
PMID:  1629079     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Transient responses of minute volume (VE), O2 uptake (VO2), CO2 output (VCO2), heart rate (HR), and cardiac output (Q) to a step change and ramp changes with slopes ranging from 33.3 to 14.3 W/min were studied in five healthy human subjects over the load range from 25 to 125 W. The ramp responses were fitted to a first-order model with a pure time delay (td) and a time constant (TC), while most of the step responses fitted better to a second-order model, consisting of a fast and a slow component. No significant asymmetry was observed between the on- and off-responses to step forcing. The mean response time (MRT = td+TC) of the incremental ramp response was prolonged, whereas the MRT of the decremental ramp response was shortened or unchanged, with decreasing ramp slope. The asymmetry was commonly observed in respiratory and gas exchange variables and, to a lesser extent, also in circulatory variables. Neural and humoral factors that might be responsible for this phenomenon are discussed.
Authors:
Y Miyamoto; Y Niizeki
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  72     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1992 Jun 
Date Detail:
Created Date:  1992-08-19     Completed Date:  1992-08-19     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2244-54     Citation Subset:  IM; S    
Affiliation:
Department of Electrical and Information Engineering, Faculty of Engineering, Yamagata University, Yonezawa, Japan.
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MeSH Terms
Descriptor/Qualifier:
Adult
Blood Circulation / physiology*
Carbon Dioxide
Cardiac Output / physiology
Exercise / physiology*
Heart Rate / physiology
Humans
Kinetics
Male
Oxygen Consumption / physiology
Pulmonary Gas Exchange / physiology
Respiration / physiology*
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide

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


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