Carotid baroreflex regulation of sympathetic nerve activity during dynamic exercise in humans

P. J. Fadel, S. Ogoh, D. E. Watenpaugh, W. Wasmund, A. Olivencia-Yurvati, M. L. Smith, P. B. Raven

Research output: Contribution to journalArticle

81 Scopus citations

Abstract

We sought to determine whether carotid baroreflex (CBR) control of muscle sympathetic nerve activity (MSNA) was altered during dynamic exercise. In five men and three women, 23.8 ± 0.7 (SE) yr of age, CBR function was evaluated at rest and during 20 min of arm cycling at 50% peak O2 uptake using 5-s periods of neck pressure and neck suction. From rest to steady-state arm cycling, mean arterial pressure (MAP) was significantly increased from 90.0 ± 2.7 to 118.7 ± 3.6 mmHg and MSNA burst frequency (microneurography at the peroneal nerve) was elevated by 51 ± 14% (P < 0.01). However, despite the marked increases in MAP and MSNA during exercise, CBR-Δ%MSNA responses elicited by the application of various levels of neck pressure and neck suction ranging from +45 to -80 Torr were not significantly different from those at rest. Furthermore, estimated baroreflex sensitivity for the control of MSNA at rest was the same as during exercise (P = 0.74) across the range of neck chamber pressures. Thus CBR control of sympathetic nerve activity appears to be preserved during moderate-intensity dynamic exercise.

Original languageEnglish
Pages (from-to)H1383-H1390
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume280
Issue number3 49-3
DOIs
StatePublished - 2001

Keywords

  • Arm exercise
  • Carotid baroreceptors
  • Mean arterial pressure
  • Neck pressure
  • Neck suction

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