[en] Simultaneous measurement of electrical admittance pleyhysmogram and ¹³³Xe clearance was carried out in human legs to determine the blood flow distributions before and after local warming. In this study, the total flow (F sub(Y)) of the leg segment was measured by admittance plethysmography, and blood flows in the muscle and the skin (Fm and Fs) by the clearance method. The blood flow in other tissues (f) was calculated from the equation; F sub(Y) = 0.65FFm + 0.1FFs + 0.25Ff, where 0.65, 0.1 and 0.25 were the volume ratios of the muscle, skin and other tissues to the leg, respectively. The blood flow distribution in the leg was determined by using the flow rates of the muscle (0.65FFm/F subF(Y)), skin (0.1FFs/F sub(Y)), and the residual tissues (0.25f/F sub(Y)). Measurements were performed on 17 healthy male subjects both at rest and after local warming of the leg for 15 min in 42 - 44⁰C water bath. The values of the flow rate obtained for the muscle, the skin and the residual tissues were 51, 41 and 8% at rest, and 32, 41 and 27% after thermal loading, respectively. The significance of the remarkable increase in the residual flow after thermal loading was discussed in detail. (author)