Cutaneous circulation during dehydration and heat stress

Abstract

Resting subjects were exposed for 12 hr to 43 C dry bulb, 28 C wet bulb, with and without rehydration. During dehydration, average weighted cutaneous opacity pulse amplitudes decreased 19.5%. An apparent relationship between calculated stroke volume and cutaneous pulse amplitudes existed. A 26% increase in heart rate offset decreases in perfusion per beat and probably contributed to a rise in diastolic pressure. Increases in skin temperature paralleled those of oral temperatures. In most subjects evaporative rates were slightly lower during dehydration. Certain dehydrating subjects maintained sweat rates at control levels but this did not prevent an increase in both oral and skin temperatures. Failure of temperature regulation in these experiments does not appear to be due to a decrease in heat transport or evaporation but rather to a lack of responsiveness of the sudomotor and vasomotor systems to increases in body temperature. Reasons for the temperature rise appear complex. evaporative weight loss; heat transport; skin temperature; temperature regulation Submitted on July 22, 1964