HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 99/1/81    most recent 01285.2004v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (15) Citing Articles via Google Scholar Google Scholar Articles by Wray, D. W. Articles by Richardson, R. S. Search for Related Content PubMed PubMed Citation Articles by Wray, D. W. Articles by Richardson, R. S.

Heterogeneous limb vascular responsiveness to shear stimuli during dynamic exercise in humans

Department of Medicine, University of California San Diego, La Jolla, California

Submitted 16 November 2004 ; accepted in final form 9 February 2005

Arm and leg vascular responsiveness to comparable shear stimuli during isolated dynamic exercise has not been assessed in humans. Consequently, six young cyclists performed incremental, intermittent handgrip exercise (arm) and knee-extensor exercise (leg) from 5 to 60% of maximal work rate (WR). Ultrasound Doppler measurements were taken in the brachial artery (BA), common femoral artery (CFA), and deep femoral artery (DFA) at rest and at each WR to assess diameter and sheer rate changes. Exercise at 60% maximum WR increased shear rate to the same degree in the CFA (314.3 ± 33.3 s^–1) and BA (303.3 ± 26.3 s^–1), but was significantly higher in the DFA (712.6 ± 88.3 s^–1). Compared with rest, exercise at 60% maximum WR did not alter CFA vessel diameter, but increased BA diameter (0.42 ± 0.01 to 0.49 ± 0.01 cm) and DFA diameter (0.59 ± 0.05 to 0.64 ± 0.04 cm). These data from the DFA demonstrate for the first time a substantial improvement in vascular reactivity in a conduit vessel only slightly distal to the CFA. However, despite comparable dilation between the BA and DFA, the slope of the relationship between vessel diameter and shear rate was much greater in the arm (2.4 x 10^–4 ± 4.6 x 10^–5 cm/s) than in either the DFA (8.9 x 10^–5 ± 1.5 x 10^–5 cm/s) or CFA (2.1 x 10^–5 ± 1.1 x 10^–5 cm/s). Together, these findings reveal a substantial heterogeneity in vascular responsiveness in the leg during dynamic exercise but demonstrate that conduit vessel dilation for a given change in shear rate is, nonetheless, reduced in the leg compared with the arm.

ultrasound Doppler; blood flow; vasodilation; shear rate

This article has been cited by other articles:

				K. E. Pyke, V. Poitras, and M. E. Tschakovsky Brachial artery flow-mediated dilation during handgrip exercise: evidence for endothelial transduction of the mean shear stimulus Am J Physiol Heart Circ Physiol, June 1, 2008; 294(6): H2669 - H2679. [Abstract] [Full Text] [PDF]

				D. W. Wray, S. K. Nishiyama, R. A. Harris, and R. S. Richardson Angiotensin II in the Elderly: Impact of Angiotensin II Type 1 Receptor Sensitivity on Peripheral Hemodynamics Hypertension, June 1, 2008; 51(6): 1611 - 1616. [Abstract] [Full Text] [PDF]

				D. H. J. Thijssen, M. Kooijman, P. C. E. de Groot, M. W. P. Bleeker, P. Smits, D. J. Green, and M. T. E. Hopman Endothelium-dependent and -independent vasodilation of the superficial femoral artery in spinal cord-injured subjects J Appl Physiol, May 1, 2008; 104(5): 1387 - 1393. [Abstract] [Full Text] [PDF]

				M. Kooijman, D. H. J. Thijssen, P. C. E. de Groot, M. W. P. Bleeker, H. J. M. van Kuppevelt, D. J. Green, G. A. Rongen, P. Smits, and M. T. E. Hopman Flow-mediated dilatation in the superficial femoral artery is nitric oxide mediated in humans J. Physiol., February 15, 2008; 586(4): 1137 - 1145. [Abstract] [Full Text] [PDF]

				D. W. Wray, S. K. Nishiyama, A. J. Donato, M. Sander, P. D. Wagner, and R. S. Richardson Endothelin-1-mediated vasoconstriction at rest and during dynamic exercise in healthy humans Am J Physiol Heart Circ Physiol, October 1, 2007; 293(4): H2550 - H2556. [Abstract] [Full Text] [PDF]

				S. K. Nishiyama, D. Walter Wray, K. Berkstresser, M. Ramaswamy, and R. S. Richardson Limb-specific differences in flow-mediated dilation: the role of shear rate J Appl Physiol, September 1, 2007; 103(3): 843 - 851. [Abstract] [Full Text] [PDF]

				T. K. Pellinger and J. R. Halliwill Effect of propranolol on sympathetically mediated leg vasoconstriction in humans J. Physiol., September 1, 2007; 583(2): 797 - 809. [Abstract] [Full Text] [PDF]

				D. W. Wray, A. J. Donato, S. K. Nishiyama, and R. S. Richardson Acute sympathetic vasoconstriction at rest and during dynamic exercise in cyclists and sedentary humans J Appl Physiol, February 1, 2007; 102(2): 704 - 712. [Abstract] [Full Text] [PDF]

				B. A. Parker, S. J. Ridout, and D. N. Proctor Age and flow-mediated dilation: a comparison of dilatory responsiveness in the brachial and popliteal arteries Am J Physiol Heart Circ Physiol, December 1, 2006; 291(6): H3043 - H3049. [Abstract] [Full Text] [PDF]

				D. W. Wray, A. Uberoi, L. Lawrenson, and R. S. Richardson Evidence of preserved endothelial function and vascular plasticity with age Am J Physiol Heart Circ Physiol, March 1, 2006; 290(3): H1271 - H1277. [Abstract] [Full Text] [PDF]

				A. J. Donato, A. Uberoi, D. W. Wray, S. Nishiyama, L. Lawrenson, and R. S. Richardson Differential effects of aging on limb blood flow in humans Am J Physiol Heart Circ Physiol, January 1, 2006; 290(1): H272 - H278. [Abstract] [Full Text] [PDF]