Kenefick Robert W, Sawka Michael N
US Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760, USA.
Sports Med. 2007;37(4-5):378-81. doi: 10.2165/00007256-200737040-00027.
This article reviews causes of marathon collapse related to physical exhaustion, heat exhaustion and dehydration. During severe exercise-heat stress (high skin and core temperatures), cardiac output can decrease below levels observed during exercise in temperate conditions. This reduced cardiac output and vasodilated skin and muscle can make it difficult to sustain blood pressure and perhaps cerebral blood flow. Dehydration can accentuate this cardiovascular strain. In contrast, excessive heat loss to the environment during cold weather may result in hypothermic collapse. Other factors contributing to post-race collapse might include reduced skeletal muscle pump activity and dehydration and prior heat stress mediated changes in cerebrovascular responses to orthostatic challenges.
本文综述了与体力衰竭、热衰竭和脱水相关的马拉松比赛中晕倒的原因。在剧烈运动热应激期间（皮肤和核心体温较高），心输出量可能会降至低于在温带条件下运动时观察到的水平。这种心输出量降低以及皮肤和肌肉血管舒张会使维持血压甚至脑血流量变得困难。脱水会加剧这种心血管负担。相比之下，寒冷天气下向环境过度散热可能导致体温过低而晕倒。导致赛后晕倒的其他因素可能包括骨骼肌泵活动减少、脱水以及先前热应激介导的脑血管对直立性挑战反应的变化。
