Hines and Brown1 in 1932 introduced the local application of cold stimuli as a procedure for the quantitative estimation of the reactivity of the vasomotor system. They were seeking a standard stimulus to increase the blood pressure. The cold pressor test has since been extensively used.2
These investigators1 describe the changes which occur when the hand is immersed in ice water: "The systolic and diastolic blood pressures immediately rise, and return to the basal in from one to two minutes. Similar results are obtained by placing a foot in cold water, but there is no augmented response by placing both hands or both feet, or all four extremities, in ice water. We assumed that the basis of this reaction is the sudden stimulation of the cutaneous nerves of temperature and pain. The response is too rapid to be the result of hormonal and chemical influences."
Sullivan JD. DEPENDENCE OF THE COLD PRESSOR REACTION ON PERIPHERAL SENSATION. JAMA. 1941;117(13):1090-1091. doi:10.1001/jama.1941.72820390002009b