β-hydroxybutyrate oxidation in exercise is impaired by low-carbohydrate and high-fat availability
Purpose: In this study, we determined ketone oxidation rates in athletes under metabolic conditions of high and low carbohydrate (CHO) and fat availability. Methods: Six healthy male athletes completed 1 h of bicycle ergometer exercise at 75% maximal power (WMax) on three occasions. Prior to exerci...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
Frontiers Media
2021
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| _version_ | 1797104392249278464 |
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| author | Dearlove, DJ Holdsworth, D Kirk, T Hodson, L Charidemou, E Kvalheim, E Stubbs, B Beevers, A Griffin, JL Evans, R Robertson, J Clarke, K Cox, PJ |
| author_facet | Dearlove, DJ Holdsworth, D Kirk, T Hodson, L Charidemou, E Kvalheim, E Stubbs, B Beevers, A Griffin, JL Evans, R Robertson, J Clarke, K Cox, PJ |
| author_sort | Dearlove, DJ |
| collection | OXFORD |
| description | Purpose: In this study, we determined ketone oxidation rates in athletes under metabolic conditions of high and low carbohydrate (CHO) and fat availability.
Methods: Six healthy male athletes completed 1 h of bicycle ergometer exercise at 75% maximal power (WMax) on three occasions. Prior to exercise, participants consumed 573 mg·kg bw−1 of a ketone ester (KE) containing a 13C label. To manipulate CHO availability, athletes undertook glycogen depleting exercise followed by isocaloric high-CHO or very-low-CHO diets. To manipulate fat availability, participants were given a continuous infusion of lipid during two visits. Using stable isotope methodology, β-hydroxybutyrate (βHB) oxidation rates were therefore investigated under the following metabolic conditions: (i) high CHO + normal fat (KE+CHO); (ii) high CHO + high fat KE+CHO+FAT); and (iii) low CHO + high fat (KE+FAT).
Results: Pre-exercise intramuscular glycogen (IMGLY) was approximately halved in the KE+FAT vs. KE+CHO and KE+CHO+FAT conditions (both p < 0.05). Blood free fatty acids (FFA) and intramuscular long-chain acylcarnitines were significantly greater in the KE+FAT vs. other conditions and in the KE+CHO+FAT vs. KE+CHO conditions before exercise. Following ingestion of the 13C labeled KE, blood βHB levels increased to ≈4.5 mM before exercise in all conditions. βHB oxidation was modestly greater in the KE+CHO vs. KE+FAT conditions (mean diff. = 0.09 g·min−1, p = 0.03; d = 0.3), tended to be greater in the KE+CHO+FAT vs. KE+FAT conditions (mean diff. = 0.07 g·min−1; p = 0.1; d = 0.3) and were the same in the KE+CHO vs. KE+CHO+FAT conditions (p < 0.05; d < 0.1). A moderate positive correlation between pre-exercise IMGLY and βHB oxidation rates during exercise was present (p = 0.04; r = 0.5). Post-exercise intramuscular βHB abundance was markedly elevated in the KE+FAT vs. KE+CHO and KE+CHO+FAT conditions (both, p < 0.001; d = 2.3).
Conclusion: βHB oxidation rates during exercise are modestly impaired by low CHO availability, independent of circulating βHB levels.
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| first_indexed | 2024-03-07T06:33:12Z |
| format | Journal article |
| id | oxford-uuid:f6bd4a0a-391d-4637-ac50-1adc5d0d9670 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:33:12Z |
| publishDate | 2021 |
| publisher | Frontiers Media |
| record_format | dspace |
| spelling | oxford-uuid:f6bd4a0a-391d-4637-ac50-1adc5d0d96702022-03-27T12:37:21Zβ-hydroxybutyrate oxidation in exercise is impaired by low-carbohydrate and high-fat availabilityJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:f6bd4a0a-391d-4637-ac50-1adc5d0d9670EnglishSymplectic ElementsFrontiers Media2021Dearlove, DJHoldsworth, DKirk, THodson, LCharidemou, EKvalheim, EStubbs, BBeevers, AGriffin, JLEvans, RRobertson, JClarke, KCox, PJPurpose: In this study, we determined ketone oxidation rates in athletes under metabolic conditions of high and low carbohydrate (CHO) and fat availability. Methods: Six healthy male athletes completed 1 h of bicycle ergometer exercise at 75% maximal power (WMax) on three occasions. Prior to exercise, participants consumed 573 mg·kg bw−1 of a ketone ester (KE) containing a 13C label. To manipulate CHO availability, athletes undertook glycogen depleting exercise followed by isocaloric high-CHO or very-low-CHO diets. To manipulate fat availability, participants were given a continuous infusion of lipid during two visits. Using stable isotope methodology, β-hydroxybutyrate (βHB) oxidation rates were therefore investigated under the following metabolic conditions: (i) high CHO + normal fat (KE+CHO); (ii) high CHO + high fat KE+CHO+FAT); and (iii) low CHO + high fat (KE+FAT). Results: Pre-exercise intramuscular glycogen (IMGLY) was approximately halved in the KE+FAT vs. KE+CHO and KE+CHO+FAT conditions (both p < 0.05). Blood free fatty acids (FFA) and intramuscular long-chain acylcarnitines were significantly greater in the KE+FAT vs. other conditions and in the KE+CHO+FAT vs. KE+CHO conditions before exercise. Following ingestion of the 13C labeled KE, blood βHB levels increased to ≈4.5 mM before exercise in all conditions. βHB oxidation was modestly greater in the KE+CHO vs. KE+FAT conditions (mean diff. = 0.09 g·min−1, p = 0.03; d = 0.3), tended to be greater in the KE+CHO+FAT vs. KE+FAT conditions (mean diff. = 0.07 g·min−1; p = 0.1; d = 0.3) and were the same in the KE+CHO vs. KE+CHO+FAT conditions (p < 0.05; d < 0.1). A moderate positive correlation between pre-exercise IMGLY and βHB oxidation rates during exercise was present (p = 0.04; r = 0.5). Post-exercise intramuscular βHB abundance was markedly elevated in the KE+FAT vs. KE+CHO and KE+CHO+FAT conditions (both, p < 0.001; d = 2.3). Conclusion: βHB oxidation rates during exercise are modestly impaired by low CHO availability, independent of circulating βHB levels. |
| spellingShingle | Dearlove, DJ Holdsworth, D Kirk, T Hodson, L Charidemou, E Kvalheim, E Stubbs, B Beevers, A Griffin, JL Evans, R Robertson, J Clarke, K Cox, PJ β-hydroxybutyrate oxidation in exercise is impaired by low-carbohydrate and high-fat availability |
| title | β-hydroxybutyrate oxidation in exercise is impaired by low-carbohydrate and high-fat availability |
| title_full | β-hydroxybutyrate oxidation in exercise is impaired by low-carbohydrate and high-fat availability |
| title_fullStr | β-hydroxybutyrate oxidation in exercise is impaired by low-carbohydrate and high-fat availability |
| title_full_unstemmed | β-hydroxybutyrate oxidation in exercise is impaired by low-carbohydrate and high-fat availability |
| title_short | β-hydroxybutyrate oxidation in exercise is impaired by low-carbohydrate and high-fat availability |
| title_sort | β hydroxybutyrate oxidation in exercise is impaired by low carbohydrate and high fat availability |
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