Cardiovascular adjustments to heat stress during prolonged exercise.

Prolonged effort in hot environments is increasing popular in extreme sports. The number of long distance athletes taking part in races in extremely warm condition, as in deserts, is larger than in the past and also the race distances are increased thus. The demanding for the heart function are higher than those challenged in the past only by few athletes and in easier conditions. This puts news challenges on the professional involved in these activities and there is a need to better understand how the cardiocirculatory system responses in these extreme environmental conditions. This review paper is focused on the mechanism of cardiovascular drift function during prolonged exercise in heat conditions. Many aspects are treated in the literature. The emerging topics treated in this paper are the sympathetic and vagal nervous activity, heart rate functioning during exercise, dehydration and hyperthermia, the relationships between heart rate and stroke volume oxygen uptake and blood flow dynamic, circulatory responses, left ventricular functions in athletes after strenuous prolonged exercise, and heart rate variability. The literature on the topic appear to be vast and address many important factors of interest for the performance development occurred in hot condition and necessary to be known for the preservation of the health of the athletes.