Arterial Smooth Muscle

Each artery contains a layer of smooth muscle that continuously contracts and relaxes to regulate blood flow. In people with chronically cold extremities, the arterial smooth-muscle system is underperforming and not vasodilating effectively in response to demand. The arterial smooth-muscle system can be trained through repeated cycles of stress and adaptation, similar to skeletal muscle. Blood flow is initially reduced (vasoconstriction) during ice-water immersion, after which the body compensates by improving vasodilation capacity.