Wilk B, Kriemler S, Keller H, Bar-Or O
Children's Exercise and Nutrition Centre, McMaster University, Hamilton, ON, Canada.
Int J Sport Nutr. 1998 Mar;8(1):1-9. doi: 10.1123/ijsn.8.1.1.
Twelve 10- to 12-year-old healthy boys performed six 70-min intermittent exercise sessions (three 20-min cycling bouts at 50% VO2max with 5 min rest in between) over a 2-week period at 35 +/- 1 degrees C, 50 +/- 5% or 60 +/- 5% relative humidity. Subjects drank grape-flavored solution with 6% carbohydrate (2% glucose, 4% sucrose) and 18.0 mmol.L-1 NaCl ad libitum. Body weight (BW), heart rate, rectal temperature, thirst, and stomach fullness perception were monitored periodically. There were no differences among the six sessions in voluntary drink intake (765-902 g), hydration level (+0.75 to +1.07%BW), sweating rate (245-263 g.m-2.hr-1), and the other physiological and perceptual variables. A positive fluid balance was achieved in 67 out of 72 sessions. Voluntary drink intake of grape-flavored carbohydrate-NaCl beverage was consistently sufficient to prevent dehydration in 10- to 12-year-old boys during repeated exposures of exercise in the heat. This effect is likely to be achieved through a combination of physiological and behavioral mechanisms.
12名10至12岁的健康男孩在35±1摄氏度、相对湿度50±5%或60±5%的环境下，于两周内进行了6次70分钟的间歇性运动（三次20分钟的骑行，强度为最大摄氧量的50%，每次之间休息5分钟）。受试者随意饮用含6%碳水化合物（2%葡萄糖、4%蔗糖）和18.0毫摩尔/升氯化钠的葡萄味溶液。定期监测体重（BW）、心率、直肠温度、口渴感和饱腹感。六次运动期间，自愿饮水量（765 - 902克）、水合水平（体重增加0.75%至1.07%）、出汗率（245 - 263克·平方米·小时-1）以及其他生理和感知变量均无差异。72次运动中有67次实现了正水平衡。在10至12岁男孩反复进行热环境运动期间，自愿饮用葡萄味碳水化合物 - 氯化钠饮料始终足以防止脱水。这种效果可能是通过生理和行为机制的结合实现的。
