Mündel Toby, Hooper Paula L, Bunn Sabrina J, Jones David A
Human Performance Laboratory, School of Sport and Exercise Sciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Exp Physiol. 2006 Nov;91(6):1007-14. doi: 10.1113/expphysiol.2006.034629. Epub 2006 Aug 17.
The purpose of the present study was twofold: first, to determine the extent to which elevated skin temperature is responsible for the hormonal and perceptual responses to passive heating; and second, to determine to what extent face-cooling can override the effects of raised skin temperature. Sixteen recreationally active, non-heat-acclimated volunteers (12 male, 4 female; age, 29 +/- 9 years, [mean +/- S.D.]) underwent a passive heat exposure for 60 min in a sauna maintained at 58 degrees C (13% relative humidity), conditions under which sweating effectively maintains core temperature. Subjects were allocated to one of two experimental groups which were matched for sex, age, body mass index, body surface area and sweating response; one group received face cooling (FC) every 5 min, whilst the other control group (CON) received none. Mean skin temperatures were elevated by approximately 4 degrees C for the 60 min duration (CON, 36.5 +/- 0.1 degrees C; FC, 35.7 +/- 0.1 degrees C; P < 0.05) but core temperature rose by only approximately 0.25 degrees C with no difference between groups. Circulating prolactin remained stable and showed no increase for the FC group, whereas concentrations increased by 102 +/- 34% (P < 0.05) for the CON group. No differences were observed between groups for heart rate, but the sensation of heat was less (P < 0.05) with FC. We suggest that a significant component of the prolactin response to moderate passive heating is mediated by facial skin temperature, and selective cooling of the face is associated with improved perception of thermal comfort. These results indicate that the temperature of only a small part of the total skin area (approximately 10%) has a disproportionately large effect on the hormonal and perceptual responses to heat stress.
其一，确定皮肤温度升高在多大程度上导致了对被动加热的激素和感知反应；其二，确定面部冷却能在多大程度上抵消皮肤温度升高的影响。16名有休闲运动习惯、未进行热适应的志愿者（12名男性，4名女性；年龄29±9岁，[平均值±标准差]）在温度保持在58℃（相对湿度13%）的桑拿房中进行了60分钟的被动热暴露，在这种条件下出汗能有效维持核心体温。受试者被分配到两个实验组之一，两组在性别、年龄、体重指数、体表面积和出汗反应方面相匹配；一组每5分钟接受一次面部冷却（FC），而另一对照组（CON）不接受面部冷却。在60分钟的时间段内，平均皮肤温度升高了约4℃（CON组为36.5±0.1℃；FC组为35.7±0.1℃；P<0.05），但核心体温仅升高了约0.25℃，两组之间无差异。FC组循环催乳素保持稳定，未升高，而CON组浓度升高了102±34%（P<0.05）。两组之间心率无差异，但FC组的热感较轻（P<0.05）。我们认为，催乳素对中度被动加热反应的一个重要组成部分是由面部皮肤温度介导的，面部的选择性冷却与热舒适度的改善有关。这些结果表明，在整个皮肤面积中仅约10%的一小部分温度对热应激的激素和感知反应有着不成比例的巨大影响。
