Luan Chenglin, Wang Yizhang, Li Junxi, Zhou Nihong, Song Guilin, Ni Zhen, Xu Chunyan, Tang Chunxue, Fu Pengyu, Wang Xintang, Gong Lijing, Zhang Enming
Key Laboratory of Exercise and Physical Fitness of Ministry of Education, Beijing Sport University, Beijing 100084, China.
China Institute of Sport and Health Science, Beijing Sport University, Beijing 100084, China.
Nutrients. 2025 Apr 7;17(7):1290. doi: 10.3390/nu17071290.
Branched-chain amino acids (BCAAs, isoleucine, leucine, and valine) are commonly applied to promote muscle protein synthesis. However, the effects of BCAAs on exercise-induced substrate metabolism, performance and post-exercise fatigue during endurance exercise remain unclear. In a double-blind cross-over design, eleven active males completed 1 h of constant load exercise (CLE) at 60% VOmax power followed by a time to exhaustion (TTE) test at 80% VOmax power after supplementation with BCAAs or placebo on consecutive three days. During exercise, indirect calorimetry was used to measure the carbohydrate (CHO) and fat oxidation rate, as well as the cycling efficiency. In addition, rating of perceived exertion (RPE) and visual analogue scale (VAS) scores were obtained at interval times during the whole period. Fingertips and venous blood ( = 8) were collected for the measurement of metabolic responses at different time points during exercise. Compared to the placebo group, the fat oxidation rate was significantly higher after 20 and 30 min of CLE ( < 0.05). The CHO oxidation rates showed a significant increase in the BCAA group during TTE ( < 0.05). Meanwhile, the cycling efficiency during TTE was significantly improved ( < 0.05). Interestingly, VAS significantly decreased post-exercise in the BCAA group ( < 0.05). Additionally, the levels of blood insulin between the two groups were significantly higher in the post-exercise period compared to the pre-exercise periods ( < 0.001), while insulin levels were significantly lower in the post-exercise period with supplemental BCAAs compared to the placebo ( < 0.001). BCAAs also enhanced the levels of blood ammonia in the post-exercise period compared to the fasting and pre-exercise periods (BCAA: < 0.01; Placebo: < 0.001). However, in the post-exercise period, blood ammonia levels were significantly lower in the BCAA group than in the placebo group ( < 0.05). This study shows the critical role of BCAAs during exercise in active males and finds that BCAA supplementation enhanced fat oxidation during the CLE, increased carbohydrate oxidation and exercise efficiency during the TTE, and reduced immediate post-exercise fatigue.
支链氨基酸（BCAAs，异亮氨酸、亮氨酸和缬氨酸）通常用于促进肌肉蛋白质合成。然而，BCAAs对耐力运动期间运动诱导的底物代谢、运动表现和运动后疲劳的影响仍不明确。在一项双盲交叉设计中，11名活跃男性在连续三天补充BCAAs或安慰剂后，以60%最大摄氧量（VOmax）的功率完成1小时的恒定负荷运动（CLE），随后以80%VOmax的功率进行疲劳时间（TTE）测试。运动期间，使用间接量热法测量碳水化合物（CHO）和脂肪氧化率以及骑行效率。此外，在整个期间的不同时间点获取主观用力程度（RPE）和视觉模拟量表（VAS）评分。在运动期间的不同时间点采集指尖和静脉血（n = 8）用于测量代谢反应。与安慰剂组相比，CLE 20分钟和30分钟后脂肪氧化率显著更高（P < 0.05）。在TTE期间，BCAA组的CHO氧化率显著增加（P < 0.05）。同时，TTE期间的骑行效率显著提高（P < 0.05）。有趣的是，BCAA组运动后VAS显著降低（P < 0.05）。此外，与运动前相比，两组运动后血胰岛素水平均显著升高（P < 0.001），而与安慰剂相比，补充BCAAs后运动后胰岛素水平显著降低（P < 0.001）。与空腹和运动前相比，BCAAs在运动后也提高了血氨水平（BCAA组：P < 0.01；安慰剂组：P < 0.001）。然而，在运动后期间，BCAA组的血氨水平显著低于安慰剂组（P < 0.05）。本研究显示了BCAAs在活跃男性运动期间的关键作用，并发现补充BCAAs可增强CLE期间的脂肪氧化，增加TTE期间的碳水化合物氧化和运动效率，并减轻运动后即刻疲劳。
