Foster C, Costill D L, Fink W J
Med Sci Sports. 1979 Spring;11(1):1-5.
Eight male and female students were studied during exercise to exhaustion on a bicycle ergometer at 80 and 100% of Vo2max following the ingestion of water (W), 75 g of glucose (G) or a liquid meal (M) (10 g protein, 12.5 g fat, 15 g CHO). When compared to the endurance ride (80% Vo2max) in the W treatment, endurance performance time was reduced by 19%, (p less than .05) (53.2 to 43.2 min) as a result of the preexercise glucose feeding (Trial G). No difference in performance at 80% Vo2max was found between the W and M trials. The preexercise feedings had no effect on exercise time to exhaustion at 100% Vo2max. During the G and M trials at 80% Vo2max, most of the subjects demonstrated a transient decline in serum glucose (less than 3.5 mM). After 30-40 min. of exercise, however, serum glucose returned to normal and was seldom low at the time of exhaustion. Serum free fatty acids (FFA) were depressed throughout the G trial. The results of these experiments indicate impaired lipid mobilization following CHO ingestion. The present data support our earlier findings (11) which demonstrate that glucose feedings 30-45 minutes before endurance exercise increase the rate of CHO oxidation and impede the mobilization of FFA, thereby reducing exercise time to exhaustion.
八名男女学生在摄入水（W）、75克葡萄糖（G）或流食（M）（10克蛋白质、12.5克脂肪、15克碳水化合物）后，在自行车测力计上进行运动至力竭，运动强度分别为最大摄氧量（Vo2max）的80%和100%。与水摄入组（W）在80%Vo2max强度下的耐力骑行相比，由于运动前摄入葡萄糖（试验G），耐力表现时间缩短了19%（p<0.05）（从53.2分钟降至43.2分钟）。在80%Vo2max强度下，水摄入组（W）和流食组（M）的表现没有差异。运动前的进食对100%Vo2max强度下的运动至力竭时间没有影响。在80%Vo2max强度的葡萄糖组（G）和流食组（M）试验中，大多数受试者的血清葡萄糖出现短暂下降（低于3.5 mM）。然而，运动30 - 40分钟后，血清葡萄糖恢复正常，在力竭时很少处于低水平。在整个葡萄糖组（G）试验中，血清游离脂肪酸（FFA）水平降低。这些实验结果表明摄入碳水化合物后脂质动员受损。目前的数据支持我们早期的研究结果（11），即耐力运动前30 - 45分钟摄入葡萄糖会增加碳水化合物的氧化速率并阻碍游离脂肪酸的动员，从而缩短运动至力竭的时间。
