Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.
Science in Sport PLC, London, United Kingdom.
J Appl Physiol (1985). 2022 Jun 1;132(6):1394-1406. doi: 10.1152/japplphysiol.00091.2022. Epub 2022 Apr 21.
We examined the effects of carbohydrate (CHO) delivery form on exogenous CHO oxidation, gastrointestinal discomfort, and exercise capacity. In a randomized repeated-measures design [after 24 h of high CHO intake (8 g·kg) and preexercise meal (2 g·kg)], nine trained males ingested 120 g CHO·h from fluid (DRINK), semisolid gel (GEL), solid jelly chew (CHEW), or a coingestion approach (MIX). Participants cycled for 180 min at 95% lactate threshold, followed by an exercise capacity test (150% lactate threshold). Peak rates of exogenous CHO oxidation (DRINK 1.56 ± 0.16, GEL 1.58 ± 0.13, CHEW 1.59 ± 0.08, MIX 1.66 ± 0.02 g·min) and oxidation efficiency (DRINK 72 ± 8%, GEL 72 ± 5%, CHEW 75 ± 5%, MIX, 75 ± 6%) were not different between trials (all > 0.05). Despite ingesting 120 g·h, participants reported minimal symptoms of gastrointestinal distress across all trials. Exercise capacity was also not significantly different (all > 0.05) between conditions (DRINK 446 ± 350, GEL 529 ± 396, CHEW 596 ± 416, MIX 469 ± 395 s). Data represent the first time that rates of exogenous CHO oxidation (via stable isotope methodology) have been simultaneously assessed with feeding strategies (i.e., preexercise CHO feeding and the different forms and combinations of CHO during exercise) commonly adopted by elite endurance athletes. We conclude that 120 g·h CHO (in a 1:0.8 ratio of maltodextrin or glucose to fructose) is a practically tolerable strategy to promote high CHO availability and oxidation during exercise. We demonstrate comparable rates of exogenous CHO oxidation from fluid, semisolid, solid, or a combination of sources. Considering the sustained high rates of total and exogenous CHO oxidation and relative lack of gastrointestinal symptoms, consuming 120 g CHO·h appears to be a well-tolerated strategy to promote high CHO availability during exercise. Additionally, this is the first time that rates of exogenous CHO oxidation have been assessed with feeding strategies (e.g., coingestion of multiple CHO forms) typically reported by endurance athletes.
我们研究了碳水化合物（CHO）输送形式对外源性 CHO 氧化、胃肠道不适和运动能力的影响。在一项随机重复测量设计中（在高 CHO 摄入（8 g·kg）和运动前餐（2 g·kg）后 24 小时），9 名训练有素的男性从液体（DRINK）、半固体凝胶（GEL）、固体果冻咀嚼（CHEW）或混合摄入方式（MIX）中摄入 120 g·h·CHO。参与者以 95%乳酸阈的速度骑自行车 180 分钟，然后进行运动能力测试（150%乳酸阈）。外源性 CHO 氧化的峰值速率（DRINK 1.56±0.16，GEL 1.58±0.13，CHEW 1.59±0.08，MIX 1.66±0.02 g·min）和氧化效率（DRINK 72±8%，GEL 72±5%，CHEW 75±5%，MIX，75±6%）在试验之间没有差异（均 > 0.05）。尽管摄入了 120 g·h，但参与者在所有试验中报告的胃肠道不适症状都很少。运动能力也没有明显差异（均 > 0.05），条件（DRINK 446±350，GEL 529±396，CHEW 596±416，MIX 469±395 s）。数据代表了首次同时评估外源性 CHO 氧化率（通过稳定同位素方法）与精英耐力运动员通常采用的喂养策略（即运动前 CHO 喂养以及运动期间不同形式和组合的 CHO）。我们得出结论，120 g·h CHO（以麦芽糊精或葡萄糖与果糖的 1:0.8 比例）是一种可耐受的策略，可以在运动过程中促进高 CHO 可用性和氧化。我们从液体、半固体、固体或多种来源的混合物中证明了外源性 CHO 氧化的可比速率。考虑到总和外源性 CHO 氧化的持续高速率以及相对缺乏胃肠道症状，摄入 120 g CHO·h 似乎是一种可耐受的策略，可以在运动过程中促进高 CHO 可用性。此外，这是首次使用通常由耐力运动员报告的喂养策略（例如，混合摄入多种 CHO 形式）评估外源性 CHO 氧化率。
