The Effect of Blood Ketone Concentration and Exercise Intensity on Exogenous Ketone Oxidation Rates in Athletes

Abstract

Supplemental digital content is available in the text.

Combined effects of a ketogenic diet and exercise training alter mitochondrial and peroxisomal substrate oxidative capacity in skeletal muscle

“…Advocates for the KD cite that improved performance is due to keto-adaptation which increases fatty acid utilization and promotes glucose sparing (80,81). Alternatively, an argument can be made for the opposing view as well since 1) mitochondria do not efficiently utilize ketone bodies (69), 2) ketones are not readily used during exercise (12), and 3) increased reliance on fatty acids during exercise can reduce exercise economy (5). Unfortunately, the present study cannot provide further clarity to this controversy since we did not include performance assessments, but further studies certainly need to be done before a consensus can be reached.…”

Exogenous Ketone Salt Supplementation and Whole-Body Cooling Do Not Improve Short-Term Physical Performance

“…Additionally, the ideal skeletal muscle saturation is between 1 and 2 mmol•L −1 (43). However, maximum ketone clearance has been shown to occur at blood ketone concentrations of ∼2 mmol•L −1 (43) and when ketone concentrations are raised from 2 to 4 mmol•L −1 , rate of ketone oxidation is unchanged (44). Therefore, ketone salt supplementation may not have increased plasma concentrations enough to result in optimal ketone uptake utilization by muscle tissue during exercise.…”

“…The two key ketolytic enzymes responsible for the utilization of ketone are catalyst 3-hydroxybutryate dehydrogenase (BDH), which reduces β-OHB back into acetoacetate, and succinyl-CoA: 3-oxoacid CoA transferase (OXCT), which transfers acetoacetate into Acetyl Co-A to be used in the Krebs cycle (5,10). These two enzymes are higher in trained muscle, as well as in type I, slow twitch muscle fibers (45), and it has recently been demonstrated that percentage of type I muscle fibers had a positive associate with rate of ketones oxidation (44). Therefore, individuals who have a predominance of type I, slow twitch fibers, or well-trained athletes, might be more suitable to gain benefits from ketones, rather than the recreational athletes who participated in the current study.…”

Efficacy of Popular Diets Applied by Endurance Athletes on Sports Performance: Beneficial or Detrimental? A Narrative Review

“…For NK-LCHF diets, three studies, two crossover (a 2 week NK-LCHF diet) [26,28] and a cross-sectional (6-mth NK-LCHF diet) study [27], also investigated the impact of NK-LCHF diets on performance and lipoprotein profiles in endurance athletes (Detailed in Table 1). Besides these ketogenic diet applications, acute [30][31][32][33][34][35][36][37][38][39] or long-term [130] administration of KBs (in a ketone ester (KE) or ketone salt (KS) form) and CHO restoration following keto-adaptation [26,[40][41][42][43][45][46][47] have also been evaluated in endurance athletes. Additionally, studies have been conducted to investigate the effects of an acute pre-exercise high-fat meal [51], and a short-term (1.5 days) fat supplementation during high-CHO diet administration [49,50].…”