Circulatory control during acute physical stress in healthy young and older men.

Persistent Link:
http://hdl.handle.net/10150/185287
Title:
Circulatory control during acute physical stress in healthy young and older men.
Author:
Taylor, John Andrew.
Issue Date:
1990
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Aging has been associated with alterations in the physiological responses to physical stressors. This study investigated the regional and systemic hemodynamic responses and venous plasma catecholamine responses to three commonly encountered physical stressors (dynamic exercise, isometric exercise, and orthostasis) in groups of young (25.9 ± 0.7 yr, mean ± SE, range 21 to 29) and older (65.0 ± 0.8 yr, mean ± SE, range 60 to 72) healthy males. In separate experimental sessions, subjects performed supine leg cycling at three submaximal levels (∼45%, ∼65%, and ∼85% of peak oxygen uptake), isometric handgrip to exhaustion (30% of maximal force), and two types of orthostatic stress (lower body negative pressure (LBNP) and standing). In general, there were no differences between the young and older subjects in any baseline hemodynamic variable or baseline plasma catecholamine concentrations. In response to all levels of leg cycling, the young and older subjects had similar arterial blood pressure responses. However, the older subjects did demonstrate an augmented forearm vasoconstriction, mediated at least in part, by greater sympathetic vasoconstriction in the skeletal muscle circulation, perhaps necessary to help offset a lower cardiac output response. In response to isometric handgrip, there was a lesser heart rate response in the older subjects, but there were no age-related differences in the selected regional hemodynamic responses, arterial blood pressure response or the plasma norepinephrine responses. Likewise, in response to both types of orthostatic stress, the older subjects demonstrated a lesser tachycardic response, but there was no decline in their ability to maintain arterial pressure. Therefore, the main conclusion of these studies is that, although aging may alter the regulatory scheme, the arterial pressure response to these forms of acute physical stress is not impaired in older humans.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Biology
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Physiological Sciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Seals, Douglas R.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleCirculatory control during acute physical stress in healthy young and older men.en_US
dc.creatorTaylor, John Andrew.en_US
dc.contributor.authorTaylor, John Andrew.en_US
dc.date.issued1990en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAging has been associated with alterations in the physiological responses to physical stressors. This study investigated the regional and systemic hemodynamic responses and venous plasma catecholamine responses to three commonly encountered physical stressors (dynamic exercise, isometric exercise, and orthostasis) in groups of young (25.9 ± 0.7 yr, mean ± SE, range 21 to 29) and older (65.0 ± 0.8 yr, mean ± SE, range 60 to 72) healthy males. In separate experimental sessions, subjects performed supine leg cycling at three submaximal levels (∼45%, ∼65%, and ∼85% of peak oxygen uptake), isometric handgrip to exhaustion (30% of maximal force), and two types of orthostatic stress (lower body negative pressure (LBNP) and standing). In general, there were no differences between the young and older subjects in any baseline hemodynamic variable or baseline plasma catecholamine concentrations. In response to all levels of leg cycling, the young and older subjects had similar arterial blood pressure responses. However, the older subjects did demonstrate an augmented forearm vasoconstriction, mediated at least in part, by greater sympathetic vasoconstriction in the skeletal muscle circulation, perhaps necessary to help offset a lower cardiac output response. In response to isometric handgrip, there was a lesser heart rate response in the older subjects, but there were no age-related differences in the selected regional hemodynamic responses, arterial blood pressure response or the plasma norepinephrine responses. Likewise, in response to both types of orthostatic stress, the older subjects demonstrated a lesser tachycardic response, but there was no decline in their ability to maintain arterial pressure. Therefore, the main conclusion of these studies is that, although aging may alter the regulatory scheme, the arterial pressure response to these forms of acute physical stress is not impaired in older humans.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBiologyen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePhysiological Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSeals, Douglas R.en_US
dc.contributor.committeememberEnoka, Roger M.en_US
dc.contributor.committeememberFregosi, Ralph F.en_US
dc.contributor.committeememberFisher, Laurel A.en_US
dc.contributor.committeememberDavis, Thomas P.-
dc.identifier.proquest9111973en_US
dc.identifier.oclc710834837en_US
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