Effects of an Exogenous Ketone Supplement on Five‐Kilometer Running Performance

Abstract

Numerous oral ketone supplements are marketed with the claim that they will rapidly induce ketosis and improve exercise performance. The purpose of this study was to assess exercise performance time and related physiological, metabolic and perceptual responses of recreational endurance runners after ingestion of a commercially available oral ketone supplement. Recreational endurance runners (n = 10; age: 20.8 ± 1.0 years; body mass: 68.9 ± 5.6 kg; height: 175.6 ± 4.9 cm) participated in a double-blind, crossover, repeated-measures study where they were randomized to 300 mg.kg-1 body weight of an oral β-hydroxybutyrate-salt + Medium Chain Triglyceride (βHB-salt+MCT) ketone supplement or a flavor matched placebo (PLA) 60 min prior to performing a 5-km running time trial (5KTT) on a treadmill. Time, HR, RPE, affect, RER, VO2, VCO2, and VE were measured during the 5-km run. The Session RPE and affect (Feeling Scale) were obtained post-5KTT. Plasma glucose, lactate and ketones were measured at baseline, 60-min post-supplement, and immediately post-5KTT. Plasma R-βHB (endogenous isomer) was elevated from baseline and throughout the entire protocol under the βHB-salt+MCT condition (p < 0.05). No significant difference (58.3 ± 100.40 s; 95% CI: -130.12 – 13.52; p = 0.100) was observed between the βHB-salt+MCT supplement (1430.0 ± 187.7 s) and the PLA (1488.3 ± 243.8 s) in time to complete the 5KTT. No other differences (p > 0.05) were noted in any of the other physiological, metabolic or perceptual measures.

Dose Response of a Novel Exogenous Ketone Supplement on Physiological, Perceptual and Performance Parameters

“…Here we repeated those ndings, while also demonstrating that dosing did not affect run performance potentially explained by insu cient ability to reach hypothesize ergogenic substrate threshold [39] as gastrointestinal symptoms were not indicated in this study cohort (unreported). However, consistent with prior ndings [19,25], we also found divergent effect of ketone administration run performance across subjects which were greater than the SWD, suggesting responders and non-responders.…”

“…We found that neither administration nor dose of βHB+MCT in uenced heart rate, RR, RER, VO 2 , VCO 2 , VE, or estimated metabolic oxidation rates. HR has elevated with ketone salts administration [15,16] or reductions in HR with ester administration [18,20], with the vast majority consistent with our ndings across exogenous ketone supplements [19,[21][22][23]25]. While most exogenous ketone evaluations have not observed changes in RER in agreement with our observations, some analyses have observed differences [8,13,14].…”

“…Ketone salts and/or βHB+MCT have not shown an ability to attenuate exercise lactate productions, consistent with the present ndings [13][14][15][16]25]. However, attenuated lactate production is more consistently observed with ester administration [8,18,20], although it does not always reach signi cance [21,22].…”

“…However, neutral and/or negative effects maybe explained in part due to gastrointestinal symptoms [18,19,21,37], while other hypothesis include insu cient circulating R-βHB [19][20][21][22][23], choice of exercise, administration without carbohydrates [23], and/or placebo comparison. Our group is the only to have conducted analyses on βHB+MCT which demonstrated non-signi cant impact on run performance [25]. Here we repeated those ndings, while also demonstrating that dosing did not affect run performance potentially explained by insu cient ability to reach hypothesize ergogenic substrate threshold [39] as gastrointestinal symptoms were not indicated in this study cohort (unreported).…”

“…Additionally, this unique mixture lowers the acute mineral and MCT load, potentially mitigating gastrointestinal impact [1]. Consequently, our group explored the metabolic and performance impact of βHB-salts and MCTs on 5-km running in well trained runners and found that this was well tolerated, altered systemic metabolism, and augmented and attenuated 8/10 and 2/10 5k runner performance, respectively [25]. However, furthering limiting our knowledge on the impact of exogenous ketones bodies, is that almost all human trials has explored single dose/dosing protocols [5,8,[13][14][15][16][17][18][19][20][21][22][23] limiting our understanding on the potential convergent and/or divergent dose-response across physiologic, metabolic, and performance parameters, with limited exception [6,8].…”