Cardiovascular responses to carotid sinus baroreceptor stimulation during moderate to severe exercise in man
- 1 February 1990
- journal article
- research article
- Published by Wiley in Acta Physiologica Scandinavica
- Vol. 138 (2) , 145-153
- https://doi.org/10.1111/j.1748-1716.1990.tb08826.x
Abstract
Our objective was to assess the importance of arterial baroreflexes in maintaining vasoconstriction in active muscle during moderate to severe exercise. Eight subjects exercised for 8-15 min on a cycle ergometer at three levels (averages 94, 194, 261 W) required 40-88% of .ovrhdot.VO2 max. Four times during each exercise level pulsatile negative pressure (-50 mm Hg) was applied over the carotid sinuses for 30 s; suction was applied at each ECG R-wave for 250-400 ms. Before and during each neck suction, femoral venous blood flow (FVBF) was measured by constant infusion thermal dilution. At 94 W neck suction significantly reduced blood pressure (BP) (15 mm Hg) and heart rate (HR) (7 beats min-1), and raised leg vascular conductance (LVC) (11.4%) without changing FVBF. At 194 W, neck suction reduced BP (9 mm Hg), HR (4 beats min-1) and FVBF (5.1%, 240 ml min-1), and raised LVC (5.2%). At 261 W, LVC was unchanged by neck suction, but BP and FVBF both fell (9 mm Hg and 650 ml min-1 or 7.4%). We conclude that competing local vasodilation and sympathetic vasoconstriction control muscle blood flow during moderate exercise, and vasoconstrictor tone can be withdrawn by baroreceptor stimulation. High levels of vasoconstrictor outflow to muscle in severe exercise may not originate from baroreflexes.Keywords
This publication has 35 references indexed in Scilit:
- Noradrenaline spillover during exercise in active versus resting skeletal muscle in manActa Physiologica Scandinavica, 1987
- Reflex Control of Blood Pressure During ExerciseAnnual Review of Physiology, 1983
- Cerebrospinal fluid adrenaline and noradrenaline in depressed patientsActa Psychiatrica Scandinavica, 1980
- The effects of changes in the carotid sinus baroreceptor activity on splanchnic blood flow in anesthetized manActa Physiologica Scandinavica, 1979
- Central and Regional Circulatory Effects of Adding Arm Exercise to Leg ExerciseActa Physiologica Scandinavica, 1977
- Circulatory adjustments to dynamic exercise and effect of physical training in normal subjects and in patients with coronary artery diseaseProgress in Cardiovascular Diseases, 1976
- Cardiovascular Responses to Changes in Carotid Sinus Transmural Pressure in ManActa Physiologica Scandinavica, 1975
- The Effect in Humans of Increased Sympathetic Activity on the Blood Flow to Active MusclesActa Medica Scandinavica, 1967
- Circulatory effects of stimulating the carotid arterial stretch receptors in man at rest and during exercise.Journal of Clinical Investigation, 1966
- On the Competition between Metabolic Vasodilatation and Neurogenic Vasoconstriction in Skeletal Muscle1Acta Physiologica Scandinavica, 1965