Podlogar Tim, Cirnski Simon, Bokal Špela, Verdel Nina, Gonzalez Javier T
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham,United Kingdom.
Faculty of Health Sciences, University of Primorska, Izola,Slovenia.
Int J Sport Nutr Exerc Metab. 2022 Aug 30;32(6):439-445. doi: 10.1123/ijsnem.2022-0067. Print 2022 Nov 1.
It was previously demonstrated that postexercise ingestion of fructose-glucose mixtures can lead to superior liver and equal muscle glycogen synthesis as compared with glucose-based carbohydrates (CHOs) only. After an overnight fast, liver glycogen stores are reduced, and based on this we hypothesized that addition of fructose to a glucose-based breakfast would lead to improved subsequent endurance exercise capacity. In this double-blind cross-over randomized study (eight males, peak oxygen uptake: 62.2 ± 5.4 ml·kg-1·min-1), participants completed two experimental trials consisting of two exercise bouts. In the afternoon of Day 1, they completed a cycling interval training session to normalize glycogen stores after which a standardized high-CHO diet was provided for 4 hr. On Day 2, in the morning, participants received 2 g/kg of CHOs in the form of glucose and rice or fructose and rice, both in a CHO ratio of 1:2. Two hours later they commenced cycling exercise session at the intensity of the first ventilatory threshold until task failure. Exercise capacity was higher in fructose and rice (137.0 ± 22.7 min) as compared with glucose and rice (130.06 ± 19.87 min; p = .046). Blood glucose and blood lactate did not differ between the trials (p > .05) and neither did CHO and fat oxidation rates (p > .05). However, due to the duration of exercise, total CHO oxidation was higher in fructose and rice (326 ± 60 g vs. 298 ± 61 g, p = .009). Present data demonstrate that addition of fructose to a glucose-based CHO source at breakfast improves endurance exercise capacity. Further studies are required to determine the mechanisms and optimal dose and ratio.
先前的研究表明，与仅摄入基于葡萄糖的碳水化合物（CHO）相比，运动后摄入果糖 - 葡萄糖混合物可使肝脏糖原合成更优，肌肉糖原合成相当。经过一夜禁食后，肝脏糖原储备减少，基于此我们推测，在基于葡萄糖的早餐中添加果糖会提高随后的耐力运动能力。在这项双盲交叉随机研究中（8名男性，峰值摄氧量：62.2±5.4 ml·kg-1·min-1），参与者完成了两项由两次运动 bout 组成的实验性试验。在第1天下午，他们完成了一次自行车间歇训练课程以使糖原储备正常化，之后提供标准化的高CHO饮食4小时。在第2天上午，参与者以葡萄糖和大米或果糖和大米的形式接受2 g/kg的CHO，两者的CHO比例均为1:2。两小时后，他们开始以第一通气阈值强度进行自行车运动，直至任务失败。与葡萄糖和大米组（130.06±19.87分钟）相比，果糖和大米组的运动能力更高（137.0±22.7分钟；p = 0.046）。两次试验之间的血糖和血乳酸没有差异（p>0.05），CHO和脂肪氧化率也没有差异（p>0.05）。然而，由于运动持续时间，果糖和大米组的总CHO氧化量更高（326±60 g对298±61 g，p = 0.009）。目前的数据表明，早餐时在基于葡萄糖的CHO来源中添加果糖可提高耐力运动能力。需要进一步的研究来确定其机制以及最佳剂量和比例。
