Finger vasodilation correlates better with tympanic than esophageal temperature.

The relationship of finger blood flow (FBF) measured by venous occlusion plethysmography to tympanic temperature (Tty) was compared with that of FBF to esophageal temperature (Tes) during exercise at 50% VO2max for 40 min at an ambient temperature of 25 degrees C. The relationship of FBF to Tes showed an inflexion as Tes increased during exercise. The slope of the regression line showing the relationship between FBF and Tes was initially moderate, and then suddenly became steeper at the inflexion point. The relationship of FBF to Tty, however, was linear, without an inflexion. The results suggest that finger vasodilation during moderate exercise correlates better with tympanic than esophageal temperature.