Effects of sauna bath on the cardiovascular system

Sauna is a form of biomedical regeneration consisting of consecutive exposure to two opposite thermal agents. Firstly, during sauna bath, a person is exposed to high temperature (ranging from 70 to100 °C) at low relative humidity. Secondly, thermal exposure is followed by body cooling. One sauna bath consists of two or three repeated cycles of heat exposure followed by cooling off. Sauna can be applied in sport, recreation and therapy. The aim of this publication is to present cardiovascular changes elicited by the sauna bath. High temperature induces cutaneous vasodilation and, consequently, an incerase in cutaneous blood flow. Myocardial contractility and heart rate increase. These changes lead to alterations of blood pressure and cardiac output. Abnormalities of the electrocardiogram pattern, changes in activity of renin-angiotensin-aldosterone and blood rheological properties are observed. Cardiovascular responses to sauna bath depend both on the mode and intensity of warming and the applied methods of cooling. The risk of the sauna bath-related cardiovascular complications in healthy persons is small. Nevertheless, it is higher in individuals, who apply excessive heat exposure in order to reduce the body mass or combine sauna bathing with physical effort or alcohol consumption. However, sauna bathing in patients with cardiovascular disease should be used cautiously and preceded by individual assessment of potential risks, considering concomitant medication and the methods of both heat exposure and, especially, cooling off.