School of Regional Development Studies, Graduate School of Human and Socio-Environmental Studies, Kanazawa University.
Faculty of Human Science, Kanazawa University.
J Nutr Sci Vitaminol (Tokyo). 2020;66(2):150-157. doi: 10.3177/jnsv.66.150.
The main purpose of this study was to investigate the influence of pre-exercise glucose ingestion after a 2.5-h fast on the endurance capacity and blood glucose response in East Asian athletes who is expected to have genetically low insulin response. A total of 8 Japanese student athletes ingested 1.5 g/kg body mass of glucose (G trial) or 0.5 g/kg body mass of artificial sweetener dissolved in water (P trial) 30 min before exercise test after consuming a standardized breakfast. The exercise test comprised 40 min cycling exercise at 50% maximal oxygen uptake (VO), immediately followed by cycling to exhaustion at 70% VO. Before analyzing the data, we grouped the subjects into two groups depending on whether they showed rapid increase in blood glucose at the onset of exercise (increase rate in LOW group is <20% and HIGH group is ≥20%) to evaluate subject's insulin response to glucose feeding. No subjects developed rebound hypoglycemia (<70 mg/dL) in the G trial of both group. Significantly higher blood glucose during exercise was recognized only in the G trial of LOW group. Although no significant difference was observed between the two trials of both group, cycling time to exhaustion in the LOW group tended to increase because of glucose ingestion. These results suggest that pre-exercise ingestion of glucose in East Asian student athletes does not induce rebound hypoglycemia regardless of difference in individual insulin responses. Furthermore, individuals with low insulin responses seem to improve endurance performance with glucose ingestion before exercise.
本研究的主要目的是调查在禁食 2.5 小时后，预先摄入葡萄糖对东亚运动员耐力能力和血糖反应的影响，这些运动员预计具有较低的胰岛素反应遗传倾向。总共 8 名日本学生运动员在标准早餐后 30 分钟，摄入 1.5 克/公斤体重的葡萄糖（G 试验）或 0.5 克/公斤体重的人工甜味剂溶解在水中（P 试验），然后进行运动测试。运动测试包括 40 分钟 50%最大摄氧量（VO）的自行车运动，随后立即以 70% VO 进行自行车直至力竭。在分析数据之前，我们根据运动开始时血糖是否快速升高（LOW 组的增加率<20%，HIGH 组的增加率≥20%）将受试者分为两组，以评估受试者对葡萄糖摄入的胰岛素反应。在两组的 G 试验中，均没有受试者出现反弹性低血糖（<70mg/dL）。仅在 LOW 组的 G 试验中，运动过程中的血糖明显升高。尽管两组的两个试验之间没有观察到显著差异，但由于葡萄糖摄入，LOW 组的力竭骑行时间趋于增加。这些结果表明，东亚学生运动员在运动前摄入葡萄糖不会引起反弹性低血糖，无论个体胰岛素反应的差异如何。此外，低胰岛素反应的个体似乎可以通过在运动前摄入葡萄糖来提高耐力表现。
