摘要:Thermoregulatory sweating during light exercise during cold air temperature transients was examined in women at two different phases of their menstrual cycle. Nine women with normal menstrual cycles participated (age=27.2±4.5 y; DuBois Surface Area=1.6±0.1 m2; % Body Fat=20.0±3.8%; heart rate maximum=195±6.1 beats·min−1, and V O 2,max=46.2±4.4 mL·kg−1 min−1). Experiments were conducted in the late fall, winter, and early spring at the same time of day (0700–0900 h). The women were studied in their early follicular (F) and mid-luteal (L) phases clothed in fatigues+GoretexTM parka during treadmill exercise (∼34% V O 2,max). Air temperature (Ta) was decreased from an initial level of 20°C/40% RH to −5.0°C (wind speed of 1 m·s−1) at a rate of −0.3°C·min−1 over 80 min. Esophageal (Tes), mean skin (Tsk) and upper arm (Tarm) temperatures, V O 2, and arm sweating rate (msw) were recorded continuously. For the first 40 min of exercise, msw was correlated with Tes (r2=0.66 in F and 0.75 in L) but became inhibited by cold Tsk during the final 40 min. Throughout the exercise/cold transient, msw was higher (P<0.05) and Tes threshold temperature was increased by 0.35°C in the L vs F. Sudomotor control was adequately predicted using a maximum likelihood estimation model combining Tes, Tsk and Tarm. The model confirmed that the msw is a function of Tes, Tsk & Tarm, increases by 22% (P<0.05) as Tes threshold is displaced upwards in the L phase. In conclusion, sweating rates in the F and L during light exercise are influenced separately by changes in skin cooling and may be highly responsive to perturbations in hormonal balance.
关键词:women ; temperature regulation ; sweating control ; cold ; hormones