Noakes T D, Rehrer N J, Maughan R J
University of Cape Town, South Africa.
Med Sci Sports Exerc. 1991 Mar;23(3):307-13.
There is now substantive evidence that the provision of exogenous carbohydrate at high rates (1-2 g. min-1) can enhance performance during prolonged exercise. This finding has revived research into the factors determining the rate of exogenous carbohydrate delivery during exercise. While the rate of muscle oxidation of exogenous carbohydrate could be determined by the rate of gastric emptying or of intestinal carbohydrate absorption or of muscle glucose uptake and oxidation, most physiologists seem to have assumed that gastric emptying is the factor that limits the rate of exogenous carbohydrate delivery during exercise. Furthermore, studies of gastric emptying have suggested that the carbohydrate content of the ingested solution is an important factor determining its rate of gastric emptying. However, the findings of recent studies employing a repeated drinking design suggest that the gastric volume and therefore the pattern of drinking during exercise will have a significant, possibly major, influence on the rate of both carbohydrate and water delivery from any solution. This review considers this evidence and its practical implications for athletes who wish to ingest carbohydrate during exercise and for exercise physiologists designing studies to optimize carbohydrate delivery to muscle during exercise. It is proposed that, if gastric volume is an important determinant of the rate of gastric emptying, a more standardized method for reporting the rates of gastric emptying of different solutions should be adopted.
目前有大量证据表明，以高速率（1 - 2克·分钟⁻¹）提供外源性碳水化合物可以提高长时间运动期间的运动表现。这一发现重新引发了对决定运动期间外源性碳水化合物输送速率的因素的研究。虽然外源性碳水化合物的肌肉氧化速率可能由胃排空速率、肠道碳水化合物吸收速率或肌肉葡萄糖摄取与氧化速率决定，但大多数生理学家似乎都认为胃排空是限制运动期间外源性碳水化合物输送速率的因素。此外，胃排空研究表明，摄入溶液中的碳水化合物含量是决定其胃排空速率的一个重要因素。然而，最近采用重复饮水设计的研究结果表明，胃容量以及因此运动期间的饮水模式将对任何溶液中碳水化合物和水的输送速率产生显著的，可能是主要的影响。这篇综述考虑了这些证据及其对希望在运动期间摄入碳水化合物的运动员以及设计研究以优化运动期间碳水化合物向肌肉输送的运动生理学家的实际意义。有人提出，如果胃容量是胃排空速率的一个重要决定因素，那么应该采用一种更标准化的方法来报告不同溶液的胃排空速率。
