Fig. 2.

Blood flow distribution at rest and during heat stress. During whole-body heat stress, cardiac output (CO) increases from ~5 to 12.5 l/min, a 2.5-fold increase. Blood flow is redirected to the skin (↑ 7–8 l/min) (39) from the splanchnic (↓ 40%) (61) and renal (↓ 15–30%) (72) regions, such that the organs comprise ~60, 5–6, and 6–7% of cardiac output with heating, respectively. Gray circles indicate the percent contribution to CO at rest, blue circles indicate a decrease in percent contribution to CO during heat stress, and red circles indicate an increase in percent contribution to CO during heat stress. Illustrations of human body organs produced by Servier Medical Art.