The lower and upper critical temperatures in male Japanese.

Critical temperatures were determined by a new estimating system called the polynomial equation method. Its consists of polynomial regression equations of metabolic rate on ambient and body temperatures and conversion equations enable to convert metabolic rate value into temperature value. Nine young adult males were tested using the system. Metabolic rate was calculated indirectly with a reference to protein metabolism and the critical temperatures were determined as follows; the lower critical air temperature to be 26.2 C, the upper critical air temperature to be 47.0 degrees C, the lower and upper mean skin temperature to be 29.2 degrees C and 36.5 degrees C, and the lower and upper critical rectal temperature to be 35.5 degrees C and 37.9 degrees C, respectively. The polynomial equation method has an advantage over the intersect method since it allows estimation of several kinds of critical temperature.