Abstract

Performing a prolonged exercise with about 65 VO2max load till exhaustion by four well trained men, the cardiac function had been measured by means of MCG,Q, SV, BP, and VO2 in five temp. conditions of 0 degree C to 40 degree C. High temp. made VO2, Q, and SV drop, but HR increased. A-VO2D became greaterin high temp. than in lower temps. MeBP fell, ICTi shortened and CaW droppedin high temp., but HDMi was almost the same or a little shortened in comparison with it at lower temps. inspite of the extension of Q-IIi. These resultssuggest the decline of cardiac function, but cannot be considered the fatigue of the heart muscle itself. The decrease of venous return because of altering the distribution of Q makes the heart filling decline and this affects the cardiac function during exercise in high temp. So, in high temperature, because the increase of skin BF due to the thermoregulation makes the venous returndecrease, the cardiac function during exercise is limited by the increasing degree of skin BF. Verf.-Referat