Cold pressor test

The cold pressor test is a cardiovascular test performed by immersing the hand into an ice-water container, usually for one minute, and measuring changes in blood pressure and heart rate. Its response is clinically indicative concerning vascular response and pulse excitability.

Physiology
Sensory afferents trigger a systemic sympathetic activation leading to marked vasodilation. The result is an elevated pulse pressure(normal is 70mm Hg), due to catecholamine release. This increased pressure fills the ventricle to a greater extent, but stroke volume decreases for by an increase in afterload.