Forearm blood flow during body temperature transients produced by leg exercise

Subjects exercised for 30 min on a bicycle ergometer at 30, 50, and 70% of maximal aerobic power in ambient temperatures of 15, 25, and 35 C and vapor pressures of less than 18 torr. Exercise was used to vary internal temperature during an experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Forearm skin temperature was fixed at about 36.5 C. Esophageal temperature was measured with a thermocouple at the level of the left atrium, and mean skin temperature was calculated from a weighted mean of thermocouple temperatures at eight skin sites. Forearm blood flow was measured by electrocapacitance plethysmography. Data are well accounted for by a linear equation independent of exercise intensity, although some subjects showed an equivocal vasodilator effect of exercise.