[Calorimetric study of thermoregulatory mechanisms at the onset of sweating and during the menstrual cycle (author's transl)]

Abstract

1 At the onset of sweating, tympanic (Tty), vaginal (Tva) and mean skin (Ts) temperature as well as the sudoral response were studied by direct and indirect calorimetry. Eight women with a normal ovulatory cycle were consecutively exposedt wice to 37 degrees C/20% rh during the follicular phase and again during the luteal phase. 2 Under our conditions, Tty may be used as an index of deep body temperature without any notable influence from ambient temperature. A weighting factor of chi = 0,7 was applied to the internal part of the body for the calculation of mean body temperature Tb. chi was determined by calorimetry, before and after the onset of sweating. 3 The onset of thermal sweating depends on a characteristic Tb corresponding to a specific caloric content of the body. Neither Tty, Tva, nor Ts, alone constitutes the specific stimulus leading to thermolysis by sweating. 4 The set point value (Tb "set") of the thermoregulatory system increases in the luteal phase, compared with that of the follicular phase. 5 Thermal regulation of the proportional control system shows a gain which is not modified during the menstrual cycle. 6 There is no relation between the shift of the set point value (Tb "set") and the increase of urine pregnandiol in the luteal phase. 7 The increase in basal body temperature and its maintenance during the post-ovulatory phase do not seem to be related to an increase in metabolic heat production.