Abstract des Autors

The purpose of this study was to examine body temperatures and sensitivity of sweating in women performing two types of exercise during two phases of the menstrual cycle. Twenty women completed a matrix of four trials: ten women performed a steady exercise (ST) at intensity of 50% VO2max for 60 min whereas the other ten women performed incremental exercise (IT) during both follicular (F) and luteal (L) phase of the menstrual cycle. All experiments were carried out at the same time of day, at an ambient temperature of 23.1+/-1.0øC and relative air humidity of 50-62%. Ear canal temperature (Tty), mean skin temperature (Tsk) as well as sweating response, estimated by changes in electrical skin resistance (ESR), were measured. Body temperature threshold and sensitivity for sweating were calculated. It was found that temperature threshold for sweating was significantly greater during phase L than F despite of the type of exercise (37.11 vs. 36.77øC for ST, and 37.19 vs. 36.79øC for IT). The IT caused greater temperature sensitivity for sweating than ST independently from the phase of the menstrual cycle (1.02 vs. 0.64 for F and 1.01 vs. 0.61 for L). Final increases in Tty did not differ between the phases of the menstrual cycle but were related to the type of exercise. Tty increased by 1.63 and 1.57øC during ST and by 0.92 and 0.82øC during IT for F and L, respectively. The data lead to the conclusion that body temperature threshold for sweating followed rather passive body heat content related to the phase of the menstrual cycle. On the other hand, temperature sensitivity for sweating followed dynamic changes in the body heat content related to the type of exercise performed. Verf.-Referat