Norepinephrine spillover from skeletal muscle during exercise in humans: role of muscle mass
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Norepinephrine spillover from skeletal muscle during exercise in humans : role of muscle mass. / Savard, G K; Richter, Erik A.; Strange, S; Kiens, Bente; Christensen, Niels Juel; Saltin, Bengt.
In: American Journal of Physiology (Consolidated), Vol. 257, No. 6 Pt 2, 1989, p. H1812-H1818.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Norepinephrine spillover from skeletal muscle during exercise in humans
T2 - role of muscle mass
AU - Savard, G K
AU - Richter, Erik A.
AU - Strange, S
AU - Kiens, Bente
AU - Christensen, Niels Juel
AU - Saltin, Bengt
PY - 1989
Y1 - 1989
N2 - The purpose of this study was to determine the effect of increasing muscle mass involvement in dynamic exercise on both sympathetic nervous activation and local hemodynamic variables of individual active and inactive skeletal muscle groups. Six male subjects performed 15-min bouts of one-legged knee extension either alone or in combination with the knee extensors of the other leg and/or with the arms. The range of work intensities varied between 24 and 71% (mean) of subjects' maximal aerobic capacity (% VO2max). Leg blood flow, measured in the femoral vein by thermodilution, was determined in both legs. Arterial and venous plasma concentrations of norepinephrine (NE) and epinephrine were analyzed, and the calculated NE spillover was used as an index of sympathetic nervous activity to the limb. NE spillover increased gradually both in the resting, and to a larger extent in the exercising legs, with a steeper rise occurring approximately 70% VO2max. These increases were not associated with any significant changes in leg blood flow or leg vascular conductance at the exercise intensities examined. These results suggest that, as the total active muscle mass increases, the rise in sympathetic nervous activity to skeletal muscle, either resting or working at a constant load, is not associated with any significant neurogenic vasoconstriction and reduction in flow or conductance through the muscle vascular bed, during whole body exercise demanding up to 71% VO2max.
AB - The purpose of this study was to determine the effect of increasing muscle mass involvement in dynamic exercise on both sympathetic nervous activation and local hemodynamic variables of individual active and inactive skeletal muscle groups. Six male subjects performed 15-min bouts of one-legged knee extension either alone or in combination with the knee extensors of the other leg and/or with the arms. The range of work intensities varied between 24 and 71% (mean) of subjects' maximal aerobic capacity (% VO2max). Leg blood flow, measured in the femoral vein by thermodilution, was determined in both legs. Arterial and venous plasma concentrations of norepinephrine (NE) and epinephrine were analyzed, and the calculated NE spillover was used as an index of sympathetic nervous activity to the limb. NE spillover increased gradually both in the resting, and to a larger extent in the exercising legs, with a steeper rise occurring approximately 70% VO2max. These increases were not associated with any significant changes in leg blood flow or leg vascular conductance at the exercise intensities examined. These results suggest that, as the total active muscle mass increases, the rise in sympathetic nervous activity to skeletal muscle, either resting or working at a constant load, is not associated with any significant neurogenic vasoconstriction and reduction in flow or conductance through the muscle vascular bed, during whole body exercise demanding up to 71% VO2max.
KW - Adult
KW - Arm
KW - Blood Pressure
KW - Cardiac Output
KW - Epinephrine
KW - Heart Rate
KW - Humans
KW - Leg
KW - Male
KW - Muscles
KW - Norepinephrine
KW - Oxygen
KW - Oxygen Consumption
KW - Physical Exertion
KW - Reference Values
KW - Regional Blood Flow
M3 - Journal article
C2 - 2603969
VL - 257
SP - H1812-H1818
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
SN - 0363-6143
IS - 6 Pt 2
ER -
ID: 154756524