운동영양학: 음료섭취가 장시간 운동시 혈장 ACTH, Cortisol농도 및 혈당 조절에 미치는 영향

The purpose of this study was to determine the effects of water intake and sports beverage intake on plasma ACTH, Cortisol, Insulin and Glucose concentration during prolonged exercise. Eight university male students participated in this study. The subjects cycled on a bicycle ergometer for 2 hours at 60% VO_2max. Total amount of fluid was net weight loss minus 1 kg after 2 hours of cycle ergometer exercise in the control group. All beverage were administered immediately prior to exercise and every 15min throughout the exercise. Water and sports beverage were comprised in the beverages used in this study. Beverages were administered in a double blind method. The results were as following. First, plasma ACTH concentration was significantly increased during exercise in the all beverage treatments. Plasma ACTH concentration at 120min of exercise were 56.94±33.57pg/ml, 34.98±19.16pg/ml and 27.30±9.5pg/ml in no fluid, water intake and sports beverage intake, respectively, that is, plasma ACTH concentration showed the most increase in no fluid and the least increase in sports beverage. Second, plasma cortisol concentration was increased during exercise in the all beverage treatments, but significantly increased only no fluid(p＜.001). That in no fluid was significantly increased at 120min of exercise. Therefore plasma cortisol concentration made no differences at 60min of exercise but was significantly higher in no fluid than in water intake and sports beverage intake at 120min of exercise(p＜.01). Third, plasma insulin concentration was significantly decreased during exercise in no fluid(p＜.01) and in water intake(p＜.05), but was insignificantly decreased in sports beverage. No differences existed among the 3 beverage treatments at both of 60min and 120min of exercise. Fourth, plama glucose concentration during exercise was significantly decreased in no fluid(p＜.001) and water intake(p＜.05). But plasma glucose concentration in sports beverage intake wasn`t changed by exercise and was maintained constantly. Therefore, as far as plasma glucose concentration at 120min of exercise was concerned, sports beverage intake group showed significantly higher concentration than the other groups(p＜.01). Consequently, this study showed that the maintenance of blood glucose concentration was helped by increasing plasma ATCH and cortisol concentration and decreasing plasma insulin concentration in no fluid and no water intake group, and gluconeogenesis of liver was decreased by relieving the increase of plasma ACTH and cortisol concentration and inhibiting the decrease of plasma insulin concentration during prolonged exercise in sports beverage intake.