The Body’s Physiological Response to High Temperatures: Exercise, Temperature Extremes And Thermal Diseases

Abstract

Under normal conditions, body temperature remains within very strait limits, with moderate thermoregulatory actions. However, during physical exercises, heat production increases, sweating processes are triggered, intense cutaneous vasodilatation occurs, while shivering and chemical thermogenesis are impaired. Despite the efficiency of the thermoregulatory mechanisms, high environmental temperatures and air humidity, coupled to strenuous muscular work and lack of acclimatization, may lead to heat stress. This may take place both indoors and outdoors, in sports competitions and in working places. The most common moderate thermal diseases, or rather, those which do not impair the thermoregulatory system, are heat syncope and heat edema. On the other hand, diseases linked to dehydration and hyperthermia are regarded as medical emergencies, and require immediately attention to avoid more serious consequences. Current research provides a description of the mechanisms of heat production and heat loss of the human body, the interference of physical and environmental factors in the process of thermoregulation and the thermal diseases triggered by excessive heat. Data are relevant for the evaluation of certain working conditions and a more effective planning, from a thermal point of view, of working facilities, schedules and clothing.