The effects of a novel substrate on exercise energetics in elite athletes

<p>The physiological ketosis of starvation makes sound evolutionary sense, as ketone bodies have several thermodynamic advantages over other nutritional substrates, in addition to their actions to conserve protein and glucose stores. Utilising the body’s metabolic responses to ketosis by deliv...

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Príomhchruthaitheoir: Cox, PJ
Rannpháirtithe: Neubauer, S
Formáid: Tráchtas
Teanga:English
Foilsithe / Cruthaithe: 2013
Ábhair:
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author Cox, PJ
author2 Neubauer, S
author_facet Neubauer, S
Cox, PJ
author_sort Cox, PJ
collection OXFORD
description <p>The physiological ketosis of starvation makes sound evolutionary sense, as ketone bodies have several thermodynamic advantages over other nutritional substrates, in addition to their actions to conserve protein and glucose stores. Utilising the body’s metabolic responses to ketosis by delivering a novel nutritional source of ketone bodies, the work in this thesis explored the metabolic effects of ketosis on physical performance in humans. First, the pharmacokinetics and dosing requirements for ketone containing drink preparations were characterised in a population of athletes and healthy controls (n = 45). Using endurance exercise as a model of physiologic stress, the functional impact of ketosis during sustained high intensity effort was investigated in high performance athletes (n = 22). It was shown that nutritional ketosis improved performance in 18/22 athletes, who set 14 new best performances during 30 min of rowing. Furthermore, when ketones and glucose were delivered together, cycling performance was improved by 2% (n = 8) following 1.5 hours of fatiguing effort, compared with optimal carbohydrate intake. Blood D-β-hydroxybutyrate reached 3-5 mM following ketone drinks, equivalent to several days of total fasting, but rapidly decreased during exercise. It was found that higher physical workloads correlated with larger decreases in plasma ketone concentration (n = 8), consistent with their oxidation as respiratory fuels. Nutritional ketosis significantly altered fuel metabolism during exercise in elite athletes (n = 10), decreasing peripheral lipolysis, skeletal muscle glycolytic intermediates, blood lactate, and branched chain amino acid release. In conclusion this work suggests a new hierarchy of substrate preference during physical stress, whereby mimicking the physiology of starvation, the energetic consequences of oxidising ketones may significantly enhance athletic performance. The extrapolation of these findings may have therapeutic implications for patient populations where energetic demands are high, and deleterious switches in substrate selection occur.</p>
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spelling oxford-uuid:7aa52ece-42e1-4ebc-ba1c-727ba1f95cb82022-03-26T20:45:25ZThe effects of a novel substrate on exercise energetics in elite athletesThesishttp://purl.org/coar/resource_type/c_db06uuid:7aa52ece-42e1-4ebc-ba1c-727ba1f95cb8Medical SciencesBiology (medical sciences)MetabolismPhysiology and anatomyEnglishOxford University Research Archive - Valet2013Cox, PJNeubauer, SClarke, KHolloway, C<p>The physiological ketosis of starvation makes sound evolutionary sense, as ketone bodies have several thermodynamic advantages over other nutritional substrates, in addition to their actions to conserve protein and glucose stores. Utilising the body’s metabolic responses to ketosis by delivering a novel nutritional source of ketone bodies, the work in this thesis explored the metabolic effects of ketosis on physical performance in humans. First, the pharmacokinetics and dosing requirements for ketone containing drink preparations were characterised in a population of athletes and healthy controls (n = 45). Using endurance exercise as a model of physiologic stress, the functional impact of ketosis during sustained high intensity effort was investigated in high performance athletes (n = 22). It was shown that nutritional ketosis improved performance in 18/22 athletes, who set 14 new best performances during 30 min of rowing. Furthermore, when ketones and glucose were delivered together, cycling performance was improved by 2% (n = 8) following 1.5 hours of fatiguing effort, compared with optimal carbohydrate intake. Blood D-β-hydroxybutyrate reached 3-5 mM following ketone drinks, equivalent to several days of total fasting, but rapidly decreased during exercise. It was found that higher physical workloads correlated with larger decreases in plasma ketone concentration (n = 8), consistent with their oxidation as respiratory fuels. Nutritional ketosis significantly altered fuel metabolism during exercise in elite athletes (n = 10), decreasing peripheral lipolysis, skeletal muscle glycolytic intermediates, blood lactate, and branched chain amino acid release. In conclusion this work suggests a new hierarchy of substrate preference during physical stress, whereby mimicking the physiology of starvation, the energetic consequences of oxidising ketones may significantly enhance athletic performance. The extrapolation of these findings may have therapeutic implications for patient populations where energetic demands are high, and deleterious switches in substrate selection occur.</p>
spellingShingle Medical Sciences
Biology (medical sciences)
Metabolism
Physiology and anatomy
Cox, PJ
The effects of a novel substrate on exercise energetics in elite athletes
title The effects of a novel substrate on exercise energetics in elite athletes
title_full The effects of a novel substrate on exercise energetics in elite athletes
title_fullStr The effects of a novel substrate on exercise energetics in elite athletes
title_full_unstemmed The effects of a novel substrate on exercise energetics in elite athletes
title_short The effects of a novel substrate on exercise energetics in elite athletes
title_sort effects of a novel substrate on exercise energetics in elite athletes
topic Medical Sciences
Biology (medical sciences)
Metabolism
Physiology and anatomy
work_keys_str_mv AT coxpj theeffectsofanovelsubstrateonexerciseenergeticsineliteathletes
AT coxpj effectsofanovelsubstrateonexerciseenergeticsineliteathletes