Thermoregulatory responses to upper body exercise.

The purpose of this study was to compare thermoregulatory responses between upper body and lower body exercise. Nine male subjects performed 60 min of arm crank (AC) and cycle (CY) exercise at the same absolute intensity (oxygen uptake = 1.61 X min-1) and at the same relative intensity (60% of ergometer specific peak oxygen uptake) in a temperate (24 degrees C, 20% rh) environment. During the absolute intensity experiments, rectal temperature and sweating rate responses were essentially the same for both modes of exercise. In addition, no differences were found for chest, back, arm, or thigh skin temperatures, but calf skin temperature was significantly (P less than 0.05) lower during arm crank than cycle exercise. During the relative intensity experiments, thermoregulatory responses were lower during arm crank than cycle exercise. In addition, we found no difference between esophageal and rectal temperature values elicited by arm crank exercise. These results indicate that the examined thermoregulatory responses are independent of the skeletal muscle mass employed and dependent upon the absolute metabolic intensity.