Owen M D, Kregel K C, Wall P T, Gisolfi C V
Med Sci Sports Exerc. 1986 Oct;18(5):568-75.
Ingesting carbohydrate beverages during exercise in cool temperatures can improve endurance performance. However, because hyperosmotic solutions leave the stomach more slowly than water, carbohydrate beverages could be less effective in minimizing the dehydration and hyperthermia that accompany exercise in the heat. To determine the effect of osmotically different beverages on prolonged (2 h) treadmill exercise (65% VO2max) in the heat (T db = 35 degrees C), five male runners (age 24 to 41 yr) performed three separate runs drinking 200 ml every 20 min of either 10% glucose polymer (GP), 10% glucose (G), or saccharin-sweetened water (WH). A fourth run was performed in a cool (T db = 25 degrees C) room and included drinking saccharin-sweetened water (WC). Drink osmolalities (Osm) for runs GP, G, WH, and WC were 194, 586, 94, and 71 mmol . kg-1, respectively. No significant differences were observed between runs in the heat (GP, G, and WH) for heart rate, rectal and mean skin temperatures, sweat rate, percent change in plasma volume, and gastric residue volume. When compared to the WC run, both the GP and G runs yielded greater (P less than 0.05) declines in percent change in plasma volume, but only the G run had a greater (P less than 0.05) gastric residue volume. Neither plasma osmolality, total protein, nor [Na+] varied between runs. Plasma glucose, insulin, and respiratory exchange ratios were similar between the GP and G runs. However, the GP run yielded the lowest (P less than 0.05) plasma glycerol values. Although gastric residue volume (r = 0.68) and final percent change in plasma volume (r = 0.69) were significantly correlated with drink osmolality, thermoregulation was similar between runs in the heat despite the beverage consumed.
在凉爽温度下运动期间摄入碳水化合物饮料可提高耐力表现。然而，由于高渗溶液离开胃的速度比水慢，碳水化合物饮料在减轻炎热环境中运动时伴随的脱水和体温过高方面可能效果较差。为了确定渗透压不同的饮料对炎热环境（干球温度 = 35摄氏度）下持续2小时的跑步机运动（65%最大摄氧量）的影响，五名男性跑步者（年龄24至41岁）进行了三次单独跑步，每隔20分钟饮用200毫升10%葡萄糖聚合物（GP）、10%葡萄糖（G）或糖精加甜水（WH）。第四次跑步在凉爽（干球温度 = 25摄氏度）的房间进行，包括饮用糖精加甜水（WC）。GP、G、WH和WC跑步的饮料渗透压分别为194、586、94和71毫摩尔·千克-1。在炎热环境下的跑步（GP、G和WH）中，心率、直肠温度和平均皮肤温度、出汗率、血浆量变化百分比和胃残余量之间未观察到显著差异。与WC跑步相比，GP和G跑步产生的血浆量变化百分比下降幅度更大（P < 0.05），但只有G跑步的胃残余量更大（P < 0.05）。各次跑步之间血浆渗透压、总蛋白或[Na+]均无变化。GP和G跑步之间的血浆葡萄糖、胰岛素和呼吸交换率相似。然而，GP跑步产生的血浆甘油值最低（P < 0.05）。尽管胃残余量（r = 0.68）和血浆量最终变化百分比（r = 0.69）与饮料渗透压显著相关，但尽管饮用了不同饮料，炎热环境下各次跑步之间的体温调节情况相似。
