Document Detail


Physiologic requirements to perform work.
MedLine Citation:
PMID:  6421217     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In order to perform, exercising muscle must be provided with an appropriate blood flow, and the composition of the incoming blood must be kept within acceptable limits. The circulatory system maintains flow by increasing cardiac output and reducing supply to many beds (such as the splanchnic circulation), while the lung regulates arterial O2 and CO2 levels by adjusting alveolar ventilation to metabolic needs. In the process, the function of many organs is temporarily sacrificed or depressed, which means that: (1) a hierarchy of functions has to be established, and (2) some compromises among the numerous needs of the exercising muscle must be made. As a result of these readjustments, the heart and lungs of the normal subject are able to provide all the support that the exercising muscle requires. It is the peripheral machinery that fails first, as demonstrated by the switch to anaerobic metabolism while blood pressure is actually increased, and O2 and CO2 levels are maintained. Thus, if the exertion level of a patient is limited by his central circulation or by his respiration, there is a definite decrement in the functional capacity of that system.
Authors:
L E Farhi
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The American review of respiratory disease     Volume:  129     ISSN:  0003-0805     ISO Abbreviation:  Am. Rev. Respir. Dis.     Publication Date:  1984 Feb 
Date Detail:
Created Date:  1984-03-22     Completed Date:  1984-03-22     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370523     Medline TA:  Am Rev Respir Dis     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  S4-5     Citation Subset:  AIM; IM; S    
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MeSH Terms
Descriptor/Qualifier:
Carbon Dioxide / blood
Cardiac Output
Cardiovascular Physiological Phenomena
Exercise Test
Humans
Muscles / blood supply,  physiology
Oxygen / blood
Physical Exertion*
Respiration
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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


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