| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Noll Physiological Research Center, The Pennsylvania State University, University Park, Pennsylvania 16802-6900
During upright tilting, blood is translocated to the dependent
veins of the legs and compensatory circulatory adjustments are
necessary to maintain arterial pressure. For examination of the effect
of age on these responses, seven young (23 ± 1 yr) and seven older
(70 ± 3 yr) men were head-up tilted to 60° in a thermoneutral
condition and during passive heating with water-perfused suits.
Measurements included heart rate (HR), cardiac output
(
c; acetylene
rebreathing technique), central venous pressure (CVP), blood pressures,
forearm blood flow (venous occlusion plethysmography), splanchnic and
renal blood flows (indocyanine green and p-aminohippurate clearance), and esophageal and mean skin temperatures. In response to
tilting in the thermoneutral condition, CVP and stroke volume decreased
to a greater extent in the young men, but HR increased more, such that
the fall in c
was similar between the two groups in the upright posture. The rise in
splanchnic vascular resistance (SVR) was greater in the older men, but
the young men increased forearm vascular resistance (FVR) to a greater
extent than the older men. The fall in
c during
combined heat stress and tilting was greater in the young compared with
older men. Only four of the young men versus six of the older men were
able to finish the second tilt without becoming presyncopal. In
summary, the older men relied on a greater increase in SVR to
compensate for a reduced ability to constrict the skin and muscle
circulations (as determined by changes in FVR) during head-up tilting.
aging; splanchnic vascular resistance; renal vascular resistance; gravity; orthostatic challenge
This article has been cited by other articles:
|
|
 |
|
  K. L. Hess, T. E. Wilson, C. L. Sauder, Z. Gao, C. A. Ray, and K. D. Monahan Aging affects the cardiovascular responses to cold stress in humans J Appl Physiol, October 1, 2009; 107(4): 1076 - 1082. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. M. Keller, D. A. Low, J. E. Wingo, R. M. Brothers, J. Hastings, S. L. Davis, and C. G. Crandall Acute volume expansion preserves orthostatic tolerance during whole-body heat stress in humans J. Physiol., March 1, 2009; 587(5): 1131 - 1139. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. A. I. Lucas, J. D. Cotter, S. Morrison, and P. N. Ainslie The effects of ageing and passive heating on cardiorespiratory and cerebrovascular responses to orthostatic stress in humans Exp Physiol, October 1, 2008; 93(10): 1104 - 1117. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. G. Crandall, T. E. Wilson, J. Marving, T. W. Vogelsang, A. Kjaer, B. Hesse, and N. H. Secher Effects of passive heating on central blood volume and ventricular dimensions in humans J. Physiol., January 1, 2008; 586(1): 293 - 301. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. E. Wilson, C. Tollund, C. C. Yoshiga, E. A. Dawson, P. Nissen, N. H. Secher, and C. G. Crandall Effects of heat and cold stress on central vascular pressure relationships during orthostasis in humans J. Physiol., November 15, 2007; 585(1): 279 - 285. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. W. Ramsey, B. J. Behnke, R. D. Prisby, and M. D. Delp Effects of aging on adipose resistance artery vasoconstriction: possible implications for orthostatic blood pressure regulation J Appl Physiol, November 1, 2007; 103(5): 1636 - 1643. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Yamasaki, T. Ushida, T. Yokoyama, M. Ando, K. Yamashita, and T. Sato Artificial Baroreflex: Clinical Application of a Bionic Baroreflex System Circulation, February 7, 2006; 113(5): 634 - 639. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. E. Wilson, J. Cui, and C. G. Crandall Mean body temperature does not modulate eccrine sweat rate during upright tilt J Appl Physiol, April 1, 2005; 98(4): 1207 - 1212. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. P. Pricher, L. A. Holowatz, J. T. Williams, J. M. Lockwood, and J. R. Halliwill Regional hemodynamics during postexercise hypotension. I. Splanchnic and renal circulations J Appl Physiol, December 1, 2004; 97(6): 2065 - 2070. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. M. Stewart and L. D. Montgomery Regional blood volume and peripheral blood flow in postural tachycardia syndrome Am J Physiol Heart Circ Physiol, September 1, 2004; 287(3): H1319 - H1327. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. E. Wilson, N. T. Kuipers, E. A. McHugh, and C. A. Ray Vestibular activation does not influence skin sympathetic nerve responses during whole body heating J Appl Physiol, August 1, 2004; 97(2): 540 - 544. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Scremin and W. L. Kenney Aging and the skin blood flow response to the unloading of baroreceptors during heat and cold stress J Appl Physiol, March 1, 2004; 96(3): 1019 - 1025. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. L. Kenney and T. A. Munce Invited Review: Aging and human temperature regulation J Appl Physiol, December 1, 2003; 95(6): 2598 - 2603. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Muller-Delp, S. A. Spier, M. W. Ramsey, L. A. Lesniewski, A. Papadopoulos, J. D. Humphrey, and M. D. Delp Effects of aging on vasoconstrictor and mechanical properties of rat skeletal muscle arterioles Am J Physiol Heart Circ Physiol, May 1, 2002; 282(5): H1843 - H1854. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
