Diurnal Variation in the Core Interthreshold Zone in Women and its Sex Difference

The core interthreshold zone (CIZ) is defined as the range between core temperature (T c ) at the onset of shivering and the T c at the onset of sweating under consistent mean skin temperatures of 28C to 30C. A previous study demonstrated a diurnal change in the CIZ for male subjects and its relationship to the cutaneous sensation threshold zone (CSZ). In the present study, diurnal changes in the CIZ and the CSZ for young Japanese female subjects were investigated using the same experimental protocol from the study of male subjects and the sex differences in these responses were then examined.