Title | Carbohydrate intake and ketosis in self-sufficient multi-stage ultramarathon runners |
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Type | Journal article |
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Authors | Edwards, K., Elliott, B. and Silva, C. |
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Abstract | Ultra-endurance athletes accumulate an energy deficit throughout their events and those competing in self-sufficient multi-stage races are particularly vulnerable due to load carriage considerations. Whilst urinary ketones have previously been noted in ultra-endurance exercise and attributed to insufficient carbohydrate (CHO) availability, not all studies have reported concomitant CHO intake. Our aim was to determine changes in blood glucose and β-hydroxybutyrate concentrations over five days (240 km) of a self-sufficient multi-stage ultramarathon in combination with quantification of energy and macronutrient intakes, estimated energy expenditure and evaluation of energy balance. Thirteen runners (8 male, 5 female, mean age 40 ± 8 years) participated in the study. Glucose and β-hydroxybutyrate were measured every day immediately post-running, and food diaries completed daily. CHO intakes of 301 ± 106 g·day−1 (4.3 ± 1.8 g·kg−1·day−1) were not sufficient to avoid ketosis (5-day mean β-hydroxybutyrate: 1.1 ± 0.6 mmol.L−1). Furthermore, ketosis was not attenuated even when CHO intake was high (9 g·kg−1·day−1). This suggests that competing in a state of ketosis may be inevitable during multi-stage events where load reduction is prioritised over energy provisions. Attenuating negative impacts associated with such a metabolic shift in athletes unaccustomed to CHO and energy restriction requires further exploration. |
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Keywords | Ketones, running, ultra-endurance, carbohydrate, performance, nutrition, energy deficit |
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Journal | Journal of Sports Sciences |
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Journal citation | 38 (4), pp. 366-374 |
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ISSN | 1466-447X |
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Year | 2020 |
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Publisher | Taylor & Francis |
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Accepted author manuscript | File Access Level Open (open metadata and files) |
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Digital Object Identifier (DOI) | https://doi.org/10.1080/02640414.2019.1702269 |
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PubMed ID | 31835963 |
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Publication dates |
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Published online | 13 Dec 2019 |
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Published in print | 2020 |
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