Abstract

The paradoxical phenomena of hyperthermia-induced vasoconstriction, hyperthermia-induced hypothermia, and hyperthermia induced arterial vasoconstriction have been observed in animal heatstroke clinical case studies (Romanovsky & Blatteis, 1996). We attempt to explain the basic mechanism behind such findings in terms of the principle of body heat conservation and natural countermeasure against heat exposure through reduction in the extent of vascular surface area exposed. One study which examined the outcome of heating a rabbit's carotid artery produced graded vasoconstriction which is proportional to temperature increase (Mustafa, Thulesius, & Ismael, 2004).These interesting results pointed out a spontaneous physiological counteractive measure to minimise organ and/or arterial surface area heat exposure through vasoconstriction which might otherwise prompt excessive heat gain/loss from the ambient environment, and/or vasodilation, should it occur.