Impaired defense of core temperature in aged humans during mild cold stress.

Impaired defense of core temperature in aged humans during mild cold stress. Research Abstract Details 

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Impaired defense of core temperature in aged humans during mild cold stress. Abstract Text:

Aged humans often exhibit an impaired defense of core temperature during cold stress. However, research documenting this response has typically used small subject samples and strong cold stimuli. The purpose of this study was to determine the responses of young and older subjects, matched for anthropometric characteristics, during mild cold stress. Thirty-six young (YS; 23 +/- 1 years, range 18-30) and 46 older (OS; 71 +/- 1 years, range 65-89) subjects underwent a slow transient cold air exposure from a thermoneutral baseline, during which esophageal (T(es)) and mean skin temperatures (T(sk)), O(2) consumption, and skin blood flow (SkBF; laser-Doppler flowmetry) were measured. Cold exposure was terminated at the onset of visible sustained shivering. Net metabolic heat production (M(net)), heat debt, predicted change in midregion temperature (DeltaT(mid)), and tissue insulation (I(t)) were calculated. Cutaneous vascular conductance (CVC) was calculated as laser-Doppler flux/mean arterial pressure and expressed as percent change from baseline (DeltaCVC(%base)). There were no baseline group differences for T(es), but OS M(net) was lower (OS: 38.0 +/- 1.1; YS: 41.9 +/- 1.1 W . m(-2), P < 0.05). T(es) was well maintained in YS but fell progressively in OS (P < 0.01 for all timepoints after 35 min). The skin vasoconstrictor response to mild cold stress was attenuated in OS (42 +/- 3 vs. 53 +/- 4 DeltaCVC(%base), P < 0.01). There were no group differences for T(sk) or I(t), while M(net) remained lower in OS (P < 0.05). The DeltaT(mid) did not account for the drop in T(es) in OS. Healthy aged humans failed to maintain T(es); however, the mechanisms underlying this response are not clear.

Impaired defense of core temperature in aged humans during mild cold stress. Publishing Authors By Initials

For similar vasoconstriction research abstracts see: vasoconstriction research

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Impaired defense of core temperature in aged humans during mild cold stress. Journal Published:

PUBLICATION TYPE: Research Support, N.I.H., Extr

Journal: American journal of physiology. Regulatory, integr

VOLUME: 292

Page Numbers: R103-8

Journal Abbreviation: Am. J. Physiol. Regul. Integr.

ISSN: 0363-6119

DAY: 25

MONTH: 05

YEAR: 2006

Impaired defense of core temperature in aged humans during mild cold stress. Information

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LANGUAGE: eng

NlmUniqueID: 100901230

Impaired defense of core temperature in aged humans during mild cold stress. Keywords Mesh Terms:

KEYWORDS: Vasoconstriction

MESH TERMS: physiology

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Grant and Affiliation Information for Impaired defense of core temperature in aged humans during mild cold stress.

AFFILIATION: Intercollege Graduate Degree Program in Physiology, Department of Kinesiology, Pennsylvania State University, University Park, PA 16802, USA. dwd141@psu.edu

Country: United States

AGENCY: United States NIA

GRANT: T32-AG-000048-28

ACRONYM: AG

MEDLINETA: Am J Physiol Regul Integr Comp

REFSOURCE: Am J Physiol Regul Integr Comp Physiol.

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