Military Physiology Laboratory, Defence Medical and Environmental Research Institute, DSO National Laboratories, 27 Medical Drive, #09-01, Singapore, 117510, Singapore.
Eur J Appl Physiol. 2010 Jul;109(5):887-98. doi: 10.1007/s00421-010-1405-y. Epub 2010 Mar 17.
Deep body temperature (T(c)), pacing strategy and fluid balance were investigated during a 21-km road race in a warm and humid environment. Thirty-one males (age 25.3 +/- 3.2 years; maximal oxygen uptake 59.1 +/- 4.2 ml kg(-1) min(-1)) volunteered for this study. Continuous T(c) responses were obtained in 25 runners. Research stations at approximately 3-km intervals permitted accurate assessment of split times and fluid intake. Environmental conditions averaged 26.4 degrees C dry bulb temperature and 81% relative humidity. Peak T(c) was 39.8 +/- 0.5 (38.5-40.7) degrees C with 24 runners achieving T(c) > 39.0 degrees C, 17 runners > or = 39.5 degrees C, and 10 runners > or = 40.0 degrees C. In 12 runners attaining peak T(c) > or = 39.8 degrees C, running speed did not differ significantly when T(c) was below or above this threshold (208 +/- 15 cf. 205 +/- 24 m min(-1); P = 0.532). Running velocity was the main significant predictor variable of T(c) at 21 km (R(2) = 0.42, P < 0.001) and was the main discriminating variable between hyperthermic (T(c) > or = 39.8 degrees C) and normothermic runners (T(c) < 39.8 degrees C) up to 11.8 km. A reverse J-shaped pacing profile characterised by a marked reduction in running speed after 6.9 km and evidence of an end-spurt in 16 runners was observed. Variables relating to fluid balance were not associated with any T(c) parameters or pacing. We conclude that hyperthermia, defined by a deep body temperature greater than 39.5 degrees C, is common in trained individuals undertaking outdoor distance running in environmental heat, without evidence of fatigue or heat illness.
在温暖潮湿的环境中进行 21 公里公路赛跑时，研究了深部体温（T(c)）、配速策略和液体平衡。31 名男性（年龄 25.3 +/- 3.2 岁；最大摄氧量 59.1 +/- 4.2 ml kg(-1) min(-1)）自愿参加了这项研究。25 名跑步者连续测量了深部体温（T(c)）。每隔约 3 公里设置一个研究站，以便准确评估分段时间和液体摄入。环境条件平均为干球温度 26.4 摄氏度，相对湿度 81%。峰值 T(c)为 39.8 +/- 0.5（38.5-40.7）摄氏度，24 名跑步者 T(c) > 39.0 摄氏度，17 名跑步者 T(c) >或= 39.5 摄氏度，10 名跑步者 T(c) >或= 40.0 摄氏度。在 12 名达到峰值 T(c) >或= 39.8 摄氏度的跑步者中，当 T(c)低于或高于该阈值时，跑步速度没有显著差异（208 +/- 15 与 205 +/- 24 m min(-1)；P = 0.532）。在 21 公里处，跑步速度是 T(c)的主要显著预测变量（R(2) = 0.42，P < 0.001），并且是区分体温过高（T(c) >或= 39.8 摄氏度）和体温正常跑步者（T(c) < 39.8 摄氏度）的主要判别变量，直至 11.8 公里。观察到一种反向 J 形配速模式，其特征是在 6.9 公里后跑步速度明显下降，并且 16 名跑步者出现终点冲刺迹象。与液体平衡相关的变量与任何 T(c)参数或配速都没有关联。我们的结论是，在环境热量下进行户外长跑的训练有素的个体中，深部体温大于 39.5 摄氏度的高温很常见，且没有疲劳或热病的迹象。
