不同血糖指数、血糖负荷的食物对人体耐力及代谢的影响

【作者】 宋永旺；

【导师】 徐晓阳；

【作者基本信息】 华南师范大学 ， 运动人体科学， 2007， 硕士

【摘要】 目的：目前国内外在运动营养领域当中，通过控制血糖指数来调节CHO摄入的方法已经开始逐渐应用，但是对更优化的反应CHO摄入的方法，血糖指数和血糖负荷结合起来来研究对人体耐力及代谢影响的文章还没有。本文试图探讨运动前连续三天进食不同血糖指数（GI）、血糖负荷（GL）食物对人体耐力及代谢的影响。方法：本方案采用平衡重复测试法。9名男子耐力运动员[年龄20.11±0.78岁，身高174±2.23cm，体重64.8±5.00kg，最大摄氧量(64.8±2.35ml.kg^-1．min^-1，最大心率（192±3次／min）]进行三个实验，每个实验之前均进行糖原耗竭运动，随后受试者随机进食三天含等热量的高血糖指数、高血糖负荷（H-H）[CHO=73％、GI=80、GL=553]，低血糖指数、低血糖负荷（L-L）[CHO=73％、GI=42、GL=249]，高血糖指数、低血糖负荷（H-L）[CHO=31％、GI=79、GL=227]的碳水化合物（CHO）食物，每个实验间隔至少7天。H-H和L-L饮食组每天提供10.0克CHO／千克体重，H-L饮食组每天提供3.0克CHO／千克体重。测试日受试者安静休息2小时，首先在水平跑台上以70％VO₂max的强度运动1小时，随后以最短时间完成10km运动耐力测试。结果：1．连续三天进食不同GI、GL的CHO食物后，L-L与H-L相比运动时间明显缩短（L-L vs H-L：48.6±1.3min vs 55.3±6.9min，P＜0.05）；2．连续三天进食不同GI、GL的CHO食物后，H-L实验组总的CHO利用量明显低于H-H和L-L实验组（P＜0.01），总的脂肪利用量明显高于H-H和L-L实验组（P＜0.01）；3．连续三天摄入不同GI、GL的CHO食物后，H-H和L-L实验组呼吸转化率（RER）明显高于H-L实验组（P＜0.05）；三组中心率、自我感觉、口渴感觉、腹部舒适度随着运动时间延长明显增加（P＜0.01），但各组之间没有明显差异（P＞0.05）。运动后40分钟L-L实验组腹部舒适效果明显好于H-H实验组（P＜0.01）；4．连续三天进食不同GI、GL的CHO食物后，H-H实验组最后一餐餐后2小时的血糖反应曲线增加面积是L-L和H-L实验组的1.5倍（P＜0.01），运动中和恢复期间H-H和L-L实验组血糖浓度明显高于H-L实验组（P＜0.01）；5．连续三天进食不同GI、GL的CHO食物后，H-L实验组血清甘油、非脂化脂肪酸浓度明显高于H-H和L-L实验组（P＜0.01），运动中和恢复期间H-L实验组明显高于L-L和H-H实验组（P＜0.01）；6．连续三天进食不同GI、GL的CHO食物后，运动过程中三个实验组血乳酸浓度之间没有明显差异（P＞0.05）。结论：在运动前三天连续进食L-L的CHO食物，比提供等热量H-L的CHO食物能更有效地提高运动耐力；连续三天的高糖膳食（H-H和L-L）似乎可以为运动员提供更多的CHO供应来源，使运动中血糖浓度保持在较高水平。连续三天进食L-L的CHO食物，运动后期底物消耗出现了由糖氧化供能转向脂肪氧化供能；连续三天的L-L的CHO食物，能够使运动员在运动中出现良好的腹部舒适状态。更多还原

【Abstract】 Purpose’This study examined the effect of three days meal with different glycemic index/glycemic load on endurance and metabolic. Methods:Nine endurance-trained male runners ( age:20, 1±0.78 years;height:174±2.23cm;body mass:64.±5.00kg; VO₂ max:64.8±2.35ml.kg^-1.min^-1;HRmax:192±3 beats.min^-1) completed three main trials that were separated by at least seven days in a counter-balanced design. After an overnight fast for 10 to 12hours, each subject completed glycogen-depleting exercise and consumed an isocaloric meal three days containing among high glycemic index and high glycemic load（CHO=73%、GI=80、GL=553 H-H）, low glycemic index and low glycemic load （CH0=73%、GI=42、GL=249 L-L） , high glycemic index and low glycemic load（ CHO=31%、GI=79, GL=227 H-L）.H-H and L-L that provided 10.0g CHO(kg^-1 bodymass) , H-L provided 3.0g CHO(kg^-1 bodymass). After two hours, the subjects were required to run at 70% VO₂max during the first one hour of the run Then they completed the remaining 10-km as fast as possible.Results 1. A better performance was found in the L-L trial when compared with the H-L trail （L-L VS H-L :48.6±1.3min VS 55.3±6.9min, P＜0.05）2. Carbohydrate oxidation was obvions higher （P＜0.01） and fat oxidation was obvious lower （P＜0.01） in the two high CHO trials i.e., H-H and L-L, when compared to that in the low CHO trail i. e. ,H-L.3. Respiratory exchange rate was obvious higher（P＜0.01） in the two high CHO trials, when compared to that in the low CHO trail. Heart rate, ratings of perceived exertion, perceived thist , abdominal discomfort were no different in the three trails. But a better abdominal discomfort was found in the L-L after forty minutes（P＜0.01）4. The 2 h incremental area under the blood glucose curve after the last breakfast was about 1.5 times larger in the H-H trial than that in L-L and H-L trials（P＜0.05）.Higher blood glucose concentrations were also observed in the two high-CHO trials during the exercise and the recovery period when compared to that in the H-L trial（P＜0.05）.5. Serum nonesterified fatty acids （NEFA） and the serum glycerol concentrations were higher in the H-L trial than that in the H-H and L-L trials throughout exercise （P＜0.05）.6. There was no difference in the blood lactate concentrations throughout the performance run in the three trails （P＞0.05）.Conculsion Consumption of three days L-L meal is more effective in improving the 10-km run time when compared to isocaloric H-H and H-L meals. It seems that consumption of three days high CHO meals can provide more CHO for runners and keep blood glucose concentrations higher. There is a relative shift in substrate utilization from CHO to fat and a better abdominal discomfortable when consumption of three days L-L meal.更多还原