In patients with heart failure, excessive sympathetic activation during exercise could interfere with exercise performance by impairing arteriolar dilation in working muscle and by adversely altering skeletal muscle metabolic behavior. To test this hypothesis, we examined the effect of sympathoinhibition with clonidine, a central sympatholytic agent, on skeletal muscle blood flow and metabolism in patients with heart failure.
Lang, C. C., Rayos, G. H., Chomsky, D. B., Wood, A. J. J., & Wilson, J. R. (1997). Effect of sympathoinhibition on exercise performance in patients with heart failure. Circulation, 96(1), 238-45. https://doi.org/10.1161/?01.CIR.96.1.238