Vascular smooth muscle and exercise

Abstract

Vascular smooth muscle is under the influence of local (metabolic, autoregulatory and endothelial), reflex (autonomic nervous system), and hormonal (norepinephrine, epinephrine, angioten‐sin, and vasopressin) regulatory mechanisms. These regulatory mechanisms interact during exercise in a coordinated manner to assure adequate tissue blood flow while maintaining arterial blood pressure. The purpose of this article is to review the literature and propose a model that analyzes the factors regulating vascular smooth muscle during exercise. Specifically, at the onset of exercise, skeletal muscle fiber activation sets in motion a series of biochemical events that increase metabolic demand and produce cellular metabolites (adenosine, H+, Pi). These metabolites have their greatest influence on vascular smooth muscle of the smallest terminal arterioles and cause relaxation. The relaxation/dilation of the terminal arteriole reduces the perfusion pressure on the upstream arterioles and the vessels relax (autoregulat...