Abstract
During exercise, the working muscle will produce large amount of metabolic heat production, the sweat glands are activated, and skin blood flow is augmented as a function of internal and skin temperature, to maintain human body's internal and skin temperature in a moderate range. Since limited data are available from simultaneous measurements of certain cardiovascular and thermoregulation variables during incremental exercise, we secured such data by simultaneous measurements heart rate, blood pressure and skin blood flow while exercised, to examined these physiological adjustments during heat production by exercise. The present result showed that during incremental exercise: (1) in order to maintain moderate muscle perfusion, the heart rate, systolic blood pressure and mean blood pressure was increased linearly with the work load; (2) the internal and skin temperature was increased linearly with the work load (metabolic heat production), but up to 77% VO □max, both temperature increased more rapidly and reach the highest when exhaustion; (3) skin blood flow (forearm and thigh) was increased linearly with the metabolic heat production, but at the heaviest work load, the skin blood flow was clearly attenuated, suggested that cutaneous vasoconstriction occurs during severe exercise.