Glycemic and insulinemic responses
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Date
2002-01-01
Authors
Tang F.C. & Lee
Journal Title
Journal ISSN
Volume Title
Publisher
臺灣營養學會
Abstract
本研究探討運動前攝食高醣對衰竭運動後血糖與胰島素反應及肌肉恆定之影響。十九位男性大學運動員以相隔一週之時間來進行兩次不同的衰竭運動：正常飲食下進行之衰竭運動是用以測定其最大攝氧量，然後再進行高醣配方飲食（～84%醣類，～13大卡／分斤體重）下之衰竭運動（85%最大攝氧量，10%斜度）；而於運動前30～60分鐘攝食此高醣配方飲食。運動前、中、後採血，運動前、後取尿。高醣飲食後，血漿葡萄糖及胰島素濃度顯著升高（p < 0.0001）。運動中，兩者則顯著下降（p < 0.0001）。運動後，則又逐步回升直到實驗終止；但是，24小時後，血漿葡萄糖濃度則又再次下降到最低點（p < 0.0001）。運動衰竭時，乳酸濃度顯著上升（p < 0.001），衰竭後，則又顯著下降到原點（p < 0.01）。運動衰竭後尿中尿素之排泄顯著減少（p < 0.05），而羥基脯胺酸及3-甲基組胺酸則顯著增加（p < 0.05）。本研究結果認為高度運動前30～60分鐘之高醣飲食並不會導致反應性低血糖症，但高強度運動在能量充足之攝食，仍可能影響到肌肉之恆定性。
This study investigated the effect of high carbohydrate (CHO) consumption prior to exercise on plasma glucose and insulin responses, and muscle homeostasis after exhaustive exercise, Nineteen male college athletes completed two exhaustive exercises: a regular trial (regular diet; to determine maximal oxygen consumption [VO2max]) and a formula trial (high CHO [~84%] formula diet, ~ 13 kcal/kg BW; 85% VO2max, 10% grade). The diet was given 60 min prior to exercise and was ingested within 30 min. Blood samples were taken before, during, and after exercise. Urinary samples were collected pre- and post-exercise. After consumption of the CHO formula diet, both plasma glucose and insulin concentrations increased significantly (p < 0.0001). During exercise, both concentrations decreased significantly (p < 0.0001), and then after completing the exercise, they gradually increased to the end of the experiment. However, after 24 h, plasma glucose concentration had decreased again and reached the lowest level (p < 0.0001). During the exhaustive period, lactate concentration significantly increased (p < 0.0001), and then after exhaustion, it significantly decreased (p < 0.01) to return to its baseline. After exhaustion, there was a significant decrease (p < 0.05) in urinary urea nitrogen excretion and a significant increase (p < 0.05) in urinary hydroxyproline and 3-methylhistidine excretions, In conclusion, pre-exercise CHO(84%) feeding does not induce transient exercise hypoglycemia during the initial ~20 min of exercise. Muscle homeostasis, however, is affected by the high-intensity exercise of 85% VO2max even if the energy provided is sufficient.
This study investigated the effect of high carbohydrate (CHO) consumption prior to exercise on plasma glucose and insulin responses, and muscle homeostasis after exhaustive exercise, Nineteen male college athletes completed two exhaustive exercises: a regular trial (regular diet; to determine maximal oxygen consumption [VO2max]) and a formula trial (high CHO [~84%] formula diet, ~ 13 kcal/kg BW; 85% VO2max, 10% grade). The diet was given 60 min prior to exercise and was ingested within 30 min. Blood samples were taken before, during, and after exercise. Urinary samples were collected pre- and post-exercise. After consumption of the CHO formula diet, both plasma glucose and insulin concentrations increased significantly (p < 0.0001). During exercise, both concentrations decreased significantly (p < 0.0001), and then after completing the exercise, they gradually increased to the end of the experiment. However, after 24 h, plasma glucose concentration had decreased again and reached the lowest level (p < 0.0001). During the exhaustive period, lactate concentration significantly increased (p < 0.0001), and then after exhaustion, it significantly decreased (p < 0.01) to return to its baseline. After exhaustion, there was a significant decrease (p < 0.05) in urinary urea nitrogen excretion and a significant increase (p < 0.05) in urinary hydroxyproline and 3-methylhistidine excretions, In conclusion, pre-exercise CHO(84%) feeding does not induce transient exercise hypoglycemia during the initial ~20 min of exercise. Muscle homeostasis, however, is affected by the high-intensity exercise of 85% VO2max even if the energy provided is sufficient.