THE CARDIAC OUTPUT IN REST AND WORK IN HUMID HEAT

Abstract

Acclimatization to humid heat seems to involve such regulations that the circulation in rest and during work in a steady state can be kept at a practically normal level. A blood vol. increased by about 5% (Forbes, Dill and Hall) and a slightly higher pulse rate are assumed to be the 2 main factors in this regulation. Circulatory failure during work develops fairly rapidly in humid heat owing to the fact that the heat dissipation is made difficult. A larger amt. of blood is demanded for the skin circulation, making maintenance of an adequate cardiac output increasingly difficult.