Esophageal, rectal, and muscle temperature during exercise

Abstract

Esophageal, rectal, and muscle temperatures were measured during submaximal work of 1 hr. duration in 5 males and 2 females with large differences in maximal O2 uptake. Average O2 uptake on the 3 submaximal work loads were 1.07, 2.09, and 2.98 liters/min., corresponding to 26, 51, and 69% of the maximal O2 uptake. The esophageal temperature was at the 3 work loads 37.29 [plus or minus] 0.08, 38.01 [plus or minus] 0.04, and 38.49 [plus or minus] 0.10[degree] C, respectively. The rectal and the quadriceps temperatures were at the end of each work period in average of 0.14[degree] C and 0.70[degree] C, respectively, higher than the corresponding esophageal temperatures. The core temperature, and probably also the temperature in the working muscle, was found to be set according to the relative work load of the individual and not to the absolute work load performed. Skin and esophageal temperatures and sweating rates were recorded in 2 subjects exercising on a 52% work load, respectively, in the same environment. The weighted mean skin temperature and the esophageal temperature were identical in the 2 subjects during work. The sweating rate was related to the external work load performed.