Sawka M N, Gonzalez R R, Young A J, Dennis R C, Valeri C R, Pandolf K B
US Army Research Institute of Environmental Medicine, Natick 01760-5007.
Am J Physiol. 1989 Aug;257(2 Pt 2):R311-6. doi: 10.1152/ajpregu.1989.257.2.R311.
The purposes of this study were the following: 1) to determine whether erythrocyte infusion alters the control of thermoregulatory sweating and 2) to demonstrate how increases and decreases of both plasma tonicity and blood volume influence the thermoregulatory control parameters of threshold temperature and sweating sensitivity. Six non-heat-acclimated and five heat-acclimated males attempted heat stress tests (HSTs) both before and shortly after (48-96 h) autologous erythrocyte infusion. The non-heat-acclimated subjects were euhydrated for both HSTs, whereas the heat-acclimated subjects were studied in a euhydrated and a hypohydrated (-5% body wt) condition both pre- and postinfusion (500 ml of solution containing approximately 60% hematocrit of autologous erythrocytes). The HSTs consisted of treadmill exercise (335 W.m-2) in a hot (35 degrees C, 45% relative humidity) environment, and esophageal temperature and local sweating rate were continuously measured during 25 min of exercise. These experiments resulted in a matrix of conditions where both plasma tonicity and blood volume were increased or decreased relative to control conditions (euhydration, preinfusion). The findings concerning thermoregulatory sweating during exercise in the heat were summarized as follows: 1) acute polycythemia decreases the threshold temperature and increases the sweating sensitivity, 2) both threshold temperature and sweating sensitivity are increased or decreased from control levels dependent on the combined influence of plasma tonicity and blood volume, and 3) equations are presented that describe how plasma tonicity and blood volume alter threshold temperature and sweating sensitivity values.
1）确定红细胞输注是否会改变体温调节性出汗的控制；2）证明血浆渗透压和血容量的增加与减少如何影响体温调节控制参数——阈值温度和出汗敏感性。六名未进行热适应和五名进行过热适应的男性在自体红细胞输注前及输注后不久（48 - 96小时）尝试进行热应激试验（HST）。未进行热适应的受试者在两次HST中均处于正常水合状态，而进行过热适应的受试者在输注前和输注后（输注500毫升含约60%自体红细胞压积的溶液）分别在正常水合和低水合（-5%体重）状态下接受研究。HST包括在炎热（35摄氏度，相对湿度45%）环境中进行跑步机运动（335瓦·米-2），并在25分钟运动期间持续测量食管温度和局部出汗率。这些实验形成了一个条件矩阵，其中血浆渗透压和血容量相对于对照条件（正常水合、输注前）均有所增加或减少。关于在热环境中运动时体温调节性出汗的研究结果总结如下：1）急性红细胞增多症会降低阈值温度并增加出汗敏感性；2）阈值温度和出汗敏感性相对于对照水平的增加或降低取决于血浆渗透压和血容量的综合影响；3）给出了描述血浆渗透压和血容量如何改变阈值温度和出汗敏感性值的方程式。
