Document Detail

Assessment of cardiovascular reflexes is of limited value in predicting maximal +Gz-tolerance.
MedLine Citation:
PMID:  1550529     Owner:  NLM     Status:  MEDLINE    
The importance of +Gz-induced loss of consciousness as a major cause of inflight incapacitation emphasizes the need for predicting +Gz-tolerance and investigating its possible determinants. The cardiovascular changes from +Gz-stress are initially counteracted reflexly by the cardiovascular autonomic system. The integrity of neural cardiovascular reflex control can be assessed by analysing the blood pressure (BP) and heart rate (HR) responses to different maneuvers, such as the Valsalva maneuver, standing and forced respiratory sinus arrhythmia. The aim of the present study was to investigate a possible relation between the cardiovascular responses to these tests and +Gz-tolerance. In 10 healthy subjects continuous Finapres BP and HR responses to the tests have been determined and correlated with their G-levels of peripheral light loss (PLL) during centrifuge-runs (0.1 G/s). Only mean BP recovery during Valsalva maneuver correlated marginally significantly with PLL (r = 0.63, p = 0.049). Cardiovascular findings were within normal range revealing no cardiovascular autonomic dysfunction. These results indicate that intact neural cardiovascular control seems to be a condition for tolerating +Gz-stress without determining maximal +Gz-tolerance. We conclude that assessment of cardiovascular reflexes may only confirm baroreflex integrity. However, they have limited value in predicting +Gz-tolerance.
E J van Lieshout; J J van Lieshout; J Krol; M Simons; J M Karemaker
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  63     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  1992 Jan 
Date Detail:
Created Date:  1992-04-17     Completed Date:  1992-04-17     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  21-6     Citation Subset:  IM; S    
Department of Aviation, Royal Netherlands Air Force, Soesterberg.
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MeSH Terms
Aerospace Medicine*
Autonomic Nervous System / physiology
Blood Pressure / physiology*
Heart Rate / physiology*
Pressoreceptors / physiology
Stress, Physiological / epidemiology,  physiopathology
Vasoconstriction / physiology

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

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