Wendt Daniël, van Loon Luc J C, Lichtenbelt Wouter D van Marken
Department of Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, The Netherlands.
Sports Med. 2007;37(8):669-82. doi: 10.2165/00007256-200737080-00002.
As a result of the inefficiency of metabolic transfer, >75% of the energy that is generated by skeletal muscle substrate oxidation is liberated as heat. During exercise, several powerful physiological mechanisms of heat loss are activated to prevent an excessive rise in body core temperature. However, a hot and humid environment can significantly add to the challenge that physical exercise imposes on the human thermoregulatory system, as heat exchange between body and environment is substantially impaired under these conditions. This can lead to serious performance decrements and an increased risk of developing heat illness. Fortunately, there are a number of strategies that athletes can use to prevent and/or reduce the dangers that are associated with exercise in the heat. In this regard, heat acclimatisation and nutritional intervention seem to be most effective. During heat acclimatisation, the temperature thresholds for both cutaneous vasodilation and the onset of sweating are lowered, which, in combination with plasma volume expansion, improve cardiovascular stability. Effective nutritional interventions include the optimisation of hydration status by the use of fluid replacement beverages. The latter should contain moderate amounts of glucose and sodium, which improve both water absorption and retention.
由于代谢转移效率低下，骨骼肌底物氧化产生的能量中超过75%以热量形式释放。运动期间，几种强大的散热生理机制被激活，以防止体核温度过度升高。然而，炎热潮湿的环境会显著增加体育锻炼对人体体温调节系统造成的挑战，因为在这些条件下，身体与环境之间的热交换会严重受损。这可能导致运动表现严重下降，并增加患热疾病的风险。幸运的是，运动员可以采用多种策略来预防和/或降低与在高温环境下运动相关的危险。在这方面，热适应和营养干预似乎最为有效。在热适应过程中，皮肤血管舒张和出汗开始的温度阈值会降低，这与血浆量增加相结合，可改善心血管稳定性。有效的营养干预措施包括通过饮用补液饮料优化水合状态。后者应含有适量的葡萄糖和钠，这既能提高水的吸收又能促进水的潴留。
