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: 100/1/51    most recent 00804.2005v1 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 PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ogoh, S. Articles by Raven, P. B. Search for Related Content PubMed PubMed Citation Articles by Ogoh, S. Articles by Raven, P. B.

Cardiopulmonary baroreflex is reset during dynamic exercise

Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas

Submitted 7 July 2005 ; accepted in final form 6 September 2005

The purpose of this study was to examine the hypothesis that the operating point of the cardiopulmonary baroreflex resets to the higher cardiac filling pressure of exercise associated with the increased cardiac filling volumes. Eight men (age 26 ± 1 yr; height 180 ± 3 cm; weight 86 ± 6 kg; means ± SE) participated in the present study. Lower body negative pressure (LBNP) was applied at 8 and 16 Torr to decrease central venous pressure (CVP) at rest and during steady-state leg cycling at 50% peak oxygen uptake (104 ± 20 W). Subsequently, two discrete infusions of 25% human serum albumin solution were administered until CVP was increased by 1.8 ± 0.6 and 2.4 ± 0.4 mmHg at rest and 2.9 ± 0.9 and 4.6 ± 0.9 mmHg during exercise. During all protocols, heart rate, arterial blood pressure, and CVP were recorded continuously. At each stage of LBNP or albumin infusion, forearm blood flow and cardiac output were measured. During exercise, forearm vascular conductance increased from 7.5 ± 0.5 to 8.7 ± 0.6 U (P = 0.024) and total systemic vascular conductance from 7.2 ± 0.2 to 13.5 ± 0.9 l·min^–1·mmHg^–1 (P < 0.001). However, there was no significant difference in the responses of both forearm vascular conductance and total systemic vascular conductance to LBNP and the infusion of albumin between rest and exercise. These data indicate that the cardiopulmonary baroreflex had been reset during exercise to the new operating point associated with the exercise-induced change in cardiac filling volume.

central blood volume; blood pressure; forearm blood flow

This article has been cited by other articles:

				S. Ogoh, J. P. Fisher, P. J. Fadel, and P. B. Raven Increases in central blood volume modulate carotid baroreflex resetting during dynamic exercise in humans J. Physiol., May 15, 2007; 581(1): 405 - 418. [Abstract] [Full Text] [PDF]

				S. Ogoh, R. M. Brothers, Q. Barnes, W. L. Eubank, M. N. Hawkins, S. Purkayastha, A. O-Yurvati, and P. B. Raven Effects of changes in central blood volume on carotid-vasomotor baroreflex sensitivity at rest and during exercise J Appl Physiol, July 1, 2006; 101(1): 68 - 75. [Abstract] [Full Text] [PDF]

				D. M. Keller, J. Cui, S. L. Davis, D. A. Low, and C. G. Crandall Heat stress enhances arterial baroreflex control of muscle sympathetic nerve activity via increased sensitivity of burst gating, not burst area, in humans J. Physiol., June 1, 2006; 573(2): 445 - 451. [Abstract] [Full Text] [PDF]