Mairiaux P, Libert J P
Unité Hygiéne et Physiologie du Travail, Université Catholique de Louvain, Bruxelles, Belgium.
Jpn J Physiol. 1987;37(4):699-714. doi: 10.2170/jjphysiol.37.699.
The influence of esophageal (Tes) and skin temperature (Tsk) variations, body heat storage, and individual parameters on the initiation of sweating was investigated in 9 unacclimated subjects during thermal transients induced by exercise (25, 50, or 75 W) and by a step change in ambient temperature from 28 degrees C to 23, 28, 36.5, 45, or 50 degrees C. Seventy-four onsets of sweating were observed during the exposures, the sweating delay averaging 3 min at 45 and 50 degrees C, 6 min at 36.5 degrees C, and 9.5 min at 28 degrees C. In warm conditions (36.5 to 50 degrees C), the onset of sweating could mainly be related both to the level of Tsk and its rate component, whereas in cooler conditions (28 and 23 degrees C), the onset of sweating could only be related to a positive rate of Tes variation, the Tsk level being low and steady. On the whole set of data, the Tes changes at the onset were inversely related to the Tsk changes. The cumulated heat storage at the onset of sweating was 37 kJ/m2 (S.D. 25). It varied not only among subjects (range: 11-66 kJ/m2) but also within subjects even when differences in thermal state prior to exercise were accounted for. Among the individual parameters investigated, the magnitude of the decrease in Tes observed in response to the start of exercise was found to have a significant effect on the sweating delay. The Tes decrease was inversely related to the subject's skinfold thickness, and in a given subject, inversely related to the preexercise Tsk. It is concluded that the results are in agreement with a summation model of internal and mean skin temperatures on the sweating drive but that they do not verify the hypothesis of a critical level of heat storage at the onset of sweating.
在9名未适应环境的受试者中，研究了食管温度（Tes）和皮肤温度（Tsk）变化、身体蓄热以及个体参数对出汗起始的影响。这些受试者在运动（25、50或75瓦）以及环境温度从28摄氏度阶跃变化至23、28、36.5、45或50摄氏度所引起的热瞬变过程中接受观察。在暴露期间观察到74次出汗起始，在45和50摄氏度时出汗延迟平均为3分钟，在36.5摄氏度时为6分钟，在28摄氏度时为9.5分钟。在温暖条件下（36.5至50摄氏度），出汗起始主要与Tsk水平及其变化率成分有关，而在较凉爽条件下（28和23摄氏度），出汗起始仅与Tes的正变化率有关，此时Tsk水平较低且稳定。在整个数据集上，出汗起始时的Tes变化与Tsk变化呈负相关。出汗起始时的累积蓄热为37 kJ/m²（标准差25）。它不仅在受试者之间有所不同（范围：11 - 66 kJ/m²），而且即使考虑了运动前热状态的差异，在个体内部也存在变化。在所研究的个体参数中，发现运动开始时观察到的Tes下降幅度对出汗延迟有显著影响。Tes下降与受试者的皮褶厚度呈负相关，并且在给定个体中，与运动前的Tsk呈负相关。得出的结论是，这些结果与内部温度和平均皮肤温度对出汗驱动的总和模型一致，但未证实出汗起始时存在临界蓄热水平的假设。
