Wells C L, Schrader T A, Stern J R, Krahenbuhl G S
Med Sci Sports Exerc. 1985 Jun;17(3):364-9.
Ten experienced male marathon runners ran 20 miles (32.18 km) on an outdoor course in a warm climate to measure responses in selected physiological variables as a result of drinking water, an electrolyte-glucose solution (ERG), or a caffeine solution (5 mg X kg-1 body weight) before and during the run. The caffeine solution and water were colored and flavored to resemble the electrolyte-glucose solution so that a double-blind condition could be maintained. Subjects ingested a different fluid in each of the three trials in a counterbalanced design. Parameters studied were: heart rate; rectal temperature; body weight; hemoglobin and hematocrit; serum glucose, sodium, potassium, chloride, and free fatty acids; perceived exertion; respiratory exchange ratio (R); and fractional utilization of VO2max (percentage of VO2max). Both R and percentage of VO2max were higher in subjects who drank the caffeine solution compared to those who drank water. Although post-run free fatty acid mean values were significantly higher than pre-run levels, there were no statistically significant differences among the fluid treatments. Since no other differences were observed, we concluded that, under the outdoor road-running conditions encountered here, these fluid replacement treatments did not differ in their effects on the parameters studied.
十名经验丰富的男性马拉松运动员在温暖气候下的户外赛道上跑了20英里（32.18公里），以测量在跑步前和跑步过程中饮用清水、电解质 - 葡萄糖溶液（ERG）或咖啡因溶液（5毫克/千克体重）后选定生理变量的反应。咖啡因溶液和清水都进行了染色和调味，使其类似于电解质 - 葡萄糖溶液，以便维持双盲条件。在平衡设计的三次试验中，受试者每次摄入不同的液体。研究的参数包括：心率；直肠温度；体重；血红蛋白和血细胞比容；血清葡萄糖、钠、钾、氯和游离脂肪酸；主观用力感觉；呼吸交换率（R）；以及最大摄氧量的分数利用率（最大摄氧量的百分比）。与饮用清水的受试者相比，饮用咖啡因溶液的受试者的呼吸交换率和最大摄氧量百分比更高。虽然跑步后游离脂肪酸的平均值显著高于跑步前水平，但在不同液体处理之间没有统计学上的显著差异。由于未观察到其他差异，我们得出结论，在此处遇到的户外公路跑步条件下，这些补液处理对所研究参数的影响没有差异。
