PURPOSE Acute ingestion of a ketone monoester, with and without co-ingestion of carbohydrate, was investigated for effects on running economy (RE), time to exhaustion (TTE), and other related indices of endurance running performance. METHODS Using a three condition, placebo-controlled, randomized crossover design, eleven male middle- and long- distance runners ran at five submaximal speeds (10 to 14 km.h-1) on a motorized treadmill for 8 min each, immediately followed by a ramp test to volitional exhaustion. Participants consumed either a 10% carbohydrate solution (CHO), a 10% carbohydrate solution with 750 mg.kg-1 body mass of a (R)-3-hydroxybutyl (R)-3-hydroxybutyrate ketone monoester (CHO + KE), or 750 mg.kg-1 body mass of the ketone monoester in flavored water (KE) before (2/3 of the dose) and during (1/3 of the dose) exercise. RESULTS βHB concentration averaged 1.8 ± 0.3 mM and 2.1 ± 0.3 mM during exercise in CHO + KE and KE, respectively. RE was lower at each submaximal running speed (ES = 0.48 to 0.98) by an average of 4.1% in KE compared to CHO, but not between CHO + KE and CHO. TTE did not differ between CHO (369 ± 116 s), CHO + KE (342 ± 99 s), or KE (333 ± 106 s) (P = 0.093). CONCLUSIONS Acute ingestion of a ketone monoester without carbohydrate, but not when co-ingested with carbohydrate, improved RE in middle- and long- distance runners at a range of submaximal running speeds, and did not alter TTE in a short duration ramp test to volitional exhaustion. Further investigation is required to examine if these differences translate into positive performance outcomes over longer durations of exercise.

中文翻译：

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快速摄入酮单酯而不同时摄入碳水化合物可提高男性耐力跑步者的跑步经济性。

目的研究急性摄入酮单酯（同时摄入或不摄入碳水化合物）对跑步经济性（RE）、力竭时间（TTE）和其他耐力跑表现相关指标的影响。方法 采用三条件、安慰剂对照、随机交叉设计，11 名男性中长跑运动员在电动跑步机上以 5 种次最大速度（10 至 14 km.h-1）各跑 8 分钟，然后立即进行意志力衰竭的斜坡测试。参与者消耗了 10% 碳水化合物溶液 (CHO)、含有 750 mg.kg-1 体重的 (R)-3-羟丁基 (R)-3-羟基丁酸酮单酯 (CHO + KE) 的 10% 碳水化合物溶液，或在运动前（2/3 剂量）和运动期间（1/3 剂量），将 750 mg.kg-1 体重的酮单酯溶于加味水 (KE) 中。结果 CHO + KE 和 KE 运动期间 βHB 浓度平均分别为 1.8 ± 0.3 mM 和 2.1 ± 0.3 mM。与 CHO 相比，KE 在每个次最大跑步速度（ES = 0.48 至 0.98）下的 RE 平均降低了 4.1%，但 CHO + KE 和 CHO 之间没有差异。CHO (369 ± 116 s)、CHO + KE (342 ± 99 s) 或 KE (333 ± 106 s) 之间的 TTE 没有差异 (P = 0.093)。结论 急性摄入不含碳水化合物的酮单酯，但与碳水化合物共同摄入时则不然，可以改善中长跑运动员在一系列次最大跑步速度下的 RE，并且不会改变短期斜坡测试中的 TTE 至意志力精疲力尽。需要进一步调查来检验这些差异是否会在较长时间的锻炼中转化为积极的表现结果。