Human cardiovascular responses to a 60-min bath at 40 degrees C

This study was designed to determine human cardiovascular responses to a 60-min bath at 40 degrees C compared with a thermoneutral bath at 34.5 degrees C. We measured mean blood pressure (MBP), heart rate (HR), skin blood flow (SBF) and core temperature in 8 healthy young males bathing at two different temperatures, 34.5 degrees C and 40 degrees C. During the thermoneutral bath (34.5 degrees C), heart rate tended to decrease, but all other variables showed no significant change. Ten min after entering the 40 degrees C bath, MBP decreased while HR and SBF increased. At the same time core temperature increased. We conclude that bathing at 40 degrees C may induce remarkable changes in the cardiovascular system by increasing core temperature when immersion in a hot bath for more than 10 min.