Hubbard R W, Bowers W D, Matthew W T, Curtis F C, Criss R E, Sheldon G M, Ratteree J W
J Appl Physiol Respir Environ Exerc Physiol. 1977 Jun;42(6):809-16. doi: 10.1152/jappl.1977.42.6.809.
A total of 252 untrained, unacclimatized, and unanesthetized laboratory rats weighing between 485 and 545 g were fasted and either run to exhaustion at 5, 20, 23, or 26 degrees C or were restrained and heated at an ambient temperature of 41.5 degrees C. The incidence of mortality associated with a wide range of work-induced hyperthermias was compared to the lethality of equivalent heat loads in the absence of physical effort. The severity of hyperthermia was calculated in degree-minutes above a base-line core temperature of 40.4 degrees C. The LD25's of run-exhausted versus restrained-heated rats were 16.8 and 30.1 deg-min, respectively. Survivors had a faster cooling rate than fatalities, but run-exhausted survivors had a slower cooling rate than restrained-heating survivors. Results indicate that 1) both the incidence of mortality and the survival time can be predicted from the severity of core heating, 2) work-related factors contribute to an increased rate of heatstroke death at low thermal loads, and 3) retrospectively, both heat-sensitive and heat-resistant groups were identified.
总共252只未经训练、未适应环境且未麻醉的实验室大鼠，体重在485至545克之间，禁食后，要么在5、20、23或26摄氏度下跑步至力竭，要么在环境温度为41.5摄氏度时进行束缚加热。将与各种工作诱发的体温过高相关的死亡率与在没有体力消耗情况下同等热负荷的致死率进行比较。体温过高的严重程度以高于基线核心温度40.4摄氏度的度数-分钟数来计算。跑步至力竭的大鼠与束缚加热的大鼠的半数致死量分别为16.8和30.1度-分钟。幸存者的降温速度比死亡者快，但跑步至力竭的幸存者的降温速度比束缚加热的幸存者慢。结果表明：1）死亡率和存活时间均可根据核心体温升高的严重程度预测；2）与工作相关的因素导致在低热负荷下中暑死亡的发生率增加；3）回顾性地确定了热敏感组和耐热组。
