Tsintzas K, Williams C
Department of Physical Education, Sports Science and Recreation Management, Loughborough University, Leicestershire, England.
Sports Med. 1998 Jan;25(1):7-23. doi: 10.2165/00007256-199825010-00002.
Carbohydrate (CHO) ingestion during exercise, in the form of CHO-electrolyte beverages, leads to performance benefits during prolonged submaximal and variable intensity exercise. However, the mechanism underlying this ergogenic effect is less clear. Euglycaemia and oxidation of blood glucose at high rates late in exercise and a decreased rate of muscle glycogen utilisation (i.e. glycogen 'sparing') have been proposed as possible mechanisms underlying the ergogenic effect of CHO ingestion. The prevalence of one or the other mechanism depends on factors such as the type and intensity of exercise, amount, type and timing of CHO ingestion, and pre-exercise nutritional and training status of study participants. The type and intensity of exercise and the effect of these on blood glucose, plasma insulin and catecholamine levels, may play a major role in determining the rate of muscle glycogen utilisation when CHO is ingested during exercise. The ingestion of CHO (except fructose) at a rate of > 45 g/h, accompanied by a significant increase in plasma insulin levels, could lead to decreased muscle glycogen utilisation (particularly in type I fibres) during exercise. Endurance training and alterations in pre-exercise muscle glycogen levels do not seem to affect exogenous glucose oxidation during submaximal exercise. Thus, at least during low intensity or intermittent exercise, CHO ingestion could result in reduced muscle glycogen utilisation in well trained individuals with high resting muscle glycogen levels. Further research needs to concentrate on factors that regulate glucose uptake and energy metabolism in different types of muscle fibres during exercise with and without CHO ingestion.
在运动期间摄入碳水化合物（CHO），以含CHO的电解质饮料的形式，在长时间次最大强度和可变强度运动中可带来运动表现的提升。然而，这种促力效应背后的机制尚不清楚。运动后期血糖正常且血糖氧化速率高以及肌肉糖原利用速率降低（即糖原“节省”）已被提出作为CHO摄入促力效应的可能机制。一种或另一种机制的普遍程度取决于运动类型和强度、CHO摄入的量、类型和时间，以及研究参与者的运动前营养和训练状态等因素。运动类型和强度以及它们对血糖、血浆胰岛素和儿茶酚胺水平的影响，可能在决定运动期间摄入CHO时肌肉糖原的利用速率方面起主要作用。以>45克/小时的速率摄入CHO（除果糖外），伴随着血浆胰岛素水平的显著升高，可能导致运动期间肌肉糖原利用减少（特别是在I型纤维中）。耐力训练和运动前肌肉糖原水平的改变似乎不会影响次最大强度运动期间的外源性葡萄糖氧化。因此，至少在低强度或间歇性运动期间，摄入CHO可能会导致静息肌肉糖原水平高的训练有素的个体肌肉糖原利用减少。进一步的研究需要集中在运动期间有和没有CHO摄入时调节不同类型肌纤维中葡萄糖摄取和能量代谢的因素上。
