Dennis S C, Noakes T D
Medical Research Council/University, Cape Town Bionergetics of Exercise Research Unit, University of Cape Town Medical School, Sports Science Institute of South Africa, Newlands.
Eur J Appl Physiol Occup Physiol. 1999 Feb;79(3):280-4. doi: 10.1007/s004210050507.
Using a 65-kg athlete running a 2 h 10 min marathon as an example, we estimated that imbalances between approximately 1400 W of heat production and dissipation would occur in ambient temperatures of 17 degrees C at 90% relative humidity (rh) to 37 degrees C at 50% rh. Because heat production during running depends on body mass and heat loss depends on surface area, intercepts between predicted heat production and maximal heat loss with increasing speeds depend on an athlete's body mass. At 35 degrees C and 60% rh, a 45-kg athlete could maintain thermal balance by running a 2 h 13 min marathon at 19.1 km x h(-1) but a 75-kg athlete would only be able run a 3 h 28 min marathon at 12.2 km x h(-1). In both cases, the production of 970-1020 W of heat would necessitate the evaporation of at least 1.5-1.6 l of sweat per hour. A lower metabolic heat production in lighter runners at any given speed may be one reason why smallness of stature is an asset in distance running.
以一名体重65公斤的运动员跑2小时10分钟的马拉松为例，我们估计，在环境温度为17摄氏度、相对湿度90%（rh）至37摄氏度、相对湿度50%（rh）的情况下，产热与散热之间大约会出现1400瓦的不平衡。由于跑步时的产热取决于体重，而散热取决于表面积，随着速度增加，预测产热与最大散热之间的截距取决于运动员的体重。在35摄氏度和60%相对湿度的条件下，一名45公斤的运动员以19.1公里·小时⁻¹的速度跑2小时13分钟的马拉松可以维持热平衡，但一名75公斤的运动员只能以12.2公里·小时⁻¹的速度跑3小时28分钟的马拉松。在这两种情况下，每小时产生970 - 1020瓦的热量将需要至少蒸发1.5 - 1.6升汗水。在任何给定速度下，较轻跑步者较低的代谢产热可能是身材矮小在长跑中成为一项优势的原因之一。
