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: 102/2/704    most recent 00984.2006v1 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 (1) 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.

Acute sympathetic vasoconstriction at rest and during dynamic exercise in cyclists and sedentary humans

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

Submitted 5 September 2006 ; accepted in final form 26 October 2006

The impact of exercise training on sympathetic activation is not well understood, especially across untrained and trained limbs in athletes. Therefore, in eight sedentary subjects (maximal oxygen consumption = 40 ± 2 ml·kg^–1·min^–1) and eight competitive cyclists (maximal oxygen consumption= 64 ± 2 ml·kg^–1·min^–1), we evaluated heart rate, blood pressure, blood flow, vascular conductance, and vascular resistance in the leg and arm during acute sympathetic stimulation [cold pressor test (CPT)]. The CPT was also performed during dynamic leg (knee extensor) or arm (handgrip) exercise at 50% of maximal work rate (WR_max) with measurements in the exercising limb. At rest, the CPT decreased vascular conductance similarly in the leg and arm of sedentary subjects (–33 ± 8% leg, –38 ± 6% arm) and cyclists (–34 ± 4% leg, –31 ± 9% arm), and during exercise CPT-induced vasoconstriction was blunted (i.e., sympatholysis) in both the leg and arm of both groups. However, the magnitude of sympatholysis was significantly different between the arm and leg of the sedentary group (–47 ± 11% arm, –25 ± 8% leg), and it was less in the arm of cyclists (–28 ± 11%) than sedentary controls. Taken together, these data provide evidence that sympathetically mediated vasoconstriction is expressed equally and globally at rest in both sedentary and trained individuals, with a differential pattern of vasoconstriction during acute exercise according to limb and exercise training status.

sympatholysis; limb specificity

This article has been cited by other articles:

				D. W. Wray, S. K. Nishiyama, and R. S. Richardson Role of {alpha}1-adrenergic vasoconstriction in the regulation of skeletal muscle blood flow with advancing age Am J Physiol Heart Circ Physiol, February 1, 2009; 296(2): H497 - H504. [Abstract] [Full Text] [PDF]

				S. Roatta, L. Arendt-Nielsen, and D. Farina Sympathetic-induced changes in discharge rate and spike-triggered average twitch torque of low-threshold motor units in humans J. Physiol., November 15, 2008; 586(22): 5561 - 5574. [Abstract] [Full Text] [PDF]

				J. M. Stewart, I. Taneja, and M. S. Medow Reduced central blood volume and cardiac output and increased vascular resistance during static handgrip exercise in postural tachycardia syndrome Am J Physiol Heart Circ Physiol, September 1, 2007; 293(3): H1908 - H1917. [Abstract] [Full Text] [PDF]