Périard Julien D, Travers Gavin J S, Racinais Sébastien, Sawka Michael N
Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Department of Life Sciences, Centre for Sports Medicine and Human Performance, Division of Sport, Health and Exercise Sciences, Brunel University London, Uxbridge, UK.
Auton Neurosci. 2016 Apr;196:52-62. doi: 10.1016/j.autneu.2016.02.002. Epub 2016 Feb 12.
This review examines the cardiovascular adaptations along with total body water and plasma volume adjustments that occur in parallel with improved heat loss responses during exercise-heat acclimation. The cardiovascular system is well recognized as an important contributor to exercise-heat acclimation that acts to minimize physiological strain, reduce the risk of serious heat illness and better sustain exercise capacity. The upright posture adopted by humans during most physical activities and the large skin surface area contribute to the circulatory and blood pressure regulation challenge of simultaneously supporting skeletal muscle blood flow and dissipating heat via increased skin blood flow and sweat secretion during exercise-heat stress. Although it was traditionally held that cardiac output increased during exercise-heat stress to primarily support elevated skin blood flow requirements, recent evidence suggests that temperature-sensitive mechanisms may also mediate an elevation in skeletal muscle blood flow. The cardiovascular adaptations supporting this challenge include an increase in total body water, plasma volume expansion, better sustainment and/or elevation of stroke volume, reduction in heart rate, improvement in ventricular filling and myocardial efficiency, and enhanced skin blood flow and sweating responses. The magnitude of these adaptations is variable and dependent on several factors such as exercise intensity, duration of exposure, frequency and total number of exposures, as well as the environmental conditions (i.e. dry or humid heat) in which acclimation occurs.
本综述探讨了运动热适应过程中发生的心血管适应性变化，以及与改善散热反应同时出现的全身水和血浆容量的调整。心血管系统被公认为运动热适应的重要贡献者，其作用是将生理压力降至最低，降低严重热疾病的风险，并更好地维持运动能力。人类在大多数体育活动中采取的直立姿势以及较大的皮肤表面积，给循环和血压调节带来了挑战，即在运动热应激期间，要同时支持骨骼肌血流，并通过增加皮肤血流和汗液分泌来散热。虽然传统观点认为运动热应激期间心输出量增加主要是为了满足升高的皮肤血流需求，但最近的证据表明，温度敏感机制也可能介导骨骼肌血流的增加。支持这一挑战的心血管适应性变化包括全身水增加、血浆容量扩张、更好地维持和/或提高每搏输出量、心率降低、心室充盈和心肌效率改善，以及皮肤血流和出汗反应增强。这些适应性变化的程度各不相同，取决于几个因素，如运动强度、暴露持续时间、暴露频率和总次数，以及适应发生时的环境条件（即干热或湿热）。
