The first physiological response to high environmental temperature is: (A) Sweating, (B) Vasodilatation, (C) Decreased heat production, (D) Non-shivering thermogenesis
Answer is B. Under mechanisms activated by heat cutaneous vasodilation comes first followed by sweating increased respiration, decreased heat production, anorexia, apathy, and ineia. Ref: Ganong&;s review of medical physiology; 23rd edition; pg: 285; Table 18-4.