Document Detail

Physiologic requirements to perform work.
MedLine Citation:
PMID:  6421217     Owner:  NLM     Status:  MEDLINE    
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.
L E Farhi
Related Documents :
15109927 - Low-dose acetazolamide reduces the hypoxic ventilatory response in the anesthetized cat.
12594137 - Accuracy of feedback-controlled oxygen delivery into a closed anaesthesia circuit for m...
9585017 - Hypoxemic resuscitation in newborn piglets: recovery of somatosensory evoked potentials...
4030567 - Submaximal exercise responses of tetraplegics and paraplegics.
1425637 - Effect of exercise to rest ratio on plasma lactate concentration at work rates above an...
8897027 - The effects of incremental submaximal exercise on circulating leukocytes in physically ...
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    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Carbon Dioxide / blood
Cardiac Output
Cardiovascular Physiological Phenomena
Exercise Test
Muscles / blood supply,  physiology
Oxygen / blood
Physical Exertion*
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

Previous Document:  The anaerobic threshold measurement to evaluate exercise performance.
Next Document:  Predicted values for clinical exercise testing.