1UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, SOUTH AFRICA.
Med Sci Sports Exerc. 2008 Jul;40(7):1193-204. doi: 10.1249/MSS.0b013e31816a7155.
Five of 28,753 cyclists participating in an annual 109-km bicycle race died, four within 24 h of the race and the fifth 17 d later. All five deaths were reported to be the consequence of exertional heatstroke. One runner of 6874 participating in an annual 56-km ultramarathon developed heatstroke and required active cooling for 10 h to achieve normothermia. The purpose of this article was to postulate (i) why only 6 of 35,627 athletes were hospitalized for heatstroke in these races, (ii) if exercise alone could have elevated their body temperatures sufficiently to cause heatstroke, and (iii) why the runner required such prolonged cooling.
Clinical and autopsy data are presented for three of the cyclists and the runner for whom access to this information was granted. Calculations were made to predict the work rates necessary to produce their measured rectal temperatures.
The rectal temperatures of two of the cyclists were 42.0 and 41.2 degrees C on hospitalization, and that of the runner was 41.8 degrees C on collapse. Standard calculations showed that in the prevailing environmental conditions and with their exercise speeds, none should have developed exertional heatstroke. The third cyclist experienced a cardiac arrest to which his elevated (rectal) temperature may have contributed.
The hyperthermic states experienced by the cases presented may have resulted from failure of their heat-losing mechanisms. Alternatively, they might have resulted from excessive endothermy, triggered by physical exertion and other unknown initiating factors. Excessive endothermy should be considered in cases of heatstroke that occur in mild to moderate environmental conditions. Furthermore, prompt initiation of cooling is crucial in all cases of suspected heatstroke.
在参加一年一度的 109 公里自行车比赛的 28753 名选手中，有 5 人死亡，其中 4 人在比赛后 24 小时内死亡，第 5 人在 17 天后死亡。所有 5 人死亡均被报告为运动性热射病的后果。在参加一年一度的 56 公里超长马拉松比赛的 6874 名选手中，有 1 人中暑，需要积极冷却 10 小时才能使体温恢复正常。本文的目的是推测：（i）为什么在这些比赛中只有 6 名 35627 名运动员因热射病住院；（ii）运动本身是否足以使他们的体温升高而导致热射病；以及（iii）为什么跑步者需要如此长时间的冷却。
为获得信息许可的 3 名自行车手和跑步者提供了临床和尸检数据。进行了计算，以预测产生他们测量的直肠温度所需的工作量。
两名自行车手的直肠温度在住院时分别为 42.0 和 41.2 摄氏度，跑步者在崩溃时的直肠温度为 41.8 摄氏度。标准计算表明，在当时的环境条件下，以他们的运动速度，任何人都不应该发生运动性热射病。第三名自行车手发生心脏骤停，其升高的（直肠）温度可能对此有贡献。
所提出的病例中出现的高温状态可能是由于其散热机制失效所致。或者，它们可能是由身体活动和其他未知启动因素引发的过度产热引起的。在轻度至中度环境条件下发生的热射病病例中，应考虑过度产热。此外，在所有疑似热射病的情况下，迅速开始冷却至关重要。
