Dataset Information
The Effect of Blood Ketone Concentration and Exercise Intensity on Exogenous Ketone Oxidation Rates in Athletes.
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ABSTRACT: Introduction
Exogenous ketones potentially provide an alternative, energetically advantageous fuel to power exercising skeletal muscle. However, there is limited evidence regarding their relative contribution to energy expenditure during exercise. Furthermore, the effect of blood ketone concentration and exercise intensity on exogenous ketone oxidation rates is unknown.Methods
Six athletes completed cycling ergometer exercise on three occasions within a single-blind, random-order controlled, crossover design study. Exercise duration was 60 min, consisting of 20-min intervals at 25%, 50%, and 75% maximal power output (WMax). Participants consumed (i) bitter flavored water (control), (ii) a low-dose ?-hydroxybutyrate (?HB) ketone monoester (KME; 252 mg·kg BW-1, "low ketosis"), or (iii) a high-dose ?HB KME (752 mg·kg BW-1, "high ketosis"). The KME contained a 13C isotope label, allowing for the determination of whole-body exogenous ?HB oxidation rates through sampled respiratory gases.Results
Despite an approximate doubling of blood ?HB concentrations between low- and high-ketosis conditions (~2 mM vs ~4.4 mM), exogenous ?HB oxidation rates were similar at rest and throughout exercise. The contribution of exogenous ?HB oxidation to energy expenditure peaked during the 25% WMax exercise intensity but was relatively low (4.46% ± 2.71%). Delta efficiency during cycling exercise was significantly greater in the low-ketosis (25.9% ± 2.1%) versus control condition (24.1% ± 1.9%; P = 0.027).Conclusions
Regardless of exercise intensity, exogenous ?HB oxidation contributes minimally to energy expenditure and is not increased by elevating circulating concentrations greater than ~2 mM. Despite low exogenous ?HB oxidation rates, exercise efficiency was significantly improved when blood ?HB concentration was raised to ~2 mM.
SUBMITTER: Dearlove DJ
PROVIDER: S-EPMC7886359 | biostudies-literature | 2021 Mar
REPOSITORIES: biostudies-literature
Publications
The Effect of Blood Ketone Concentration and Exercise Intensity on Exogenous Ketone Oxidation Rates in Athletes.
Medicine and science in sports and exercise 20210301 3
<h4>Introduction</h4>Exogenous ketones potentially provide an alternative, energetically advantageous fuel to power exercising skeletal muscle. However, there is limited evidence regarding their relative contribution to energy expenditure during exercise. Furthermore, the effect of blood ketone concentration and exercise intensity on exogenous ketone oxidation rates is unknown.<h4>Methods</h4>Six athletes completed cycling ergometer exercise on three occasions within a single-blind, random-order ...[more]