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No acetyl group deficit is evident at the onset of exercise at 90% of maximal oxygen uptake in humans.

Marwood, S, Constantin-Teodosiou, D, Casey, E, Whyte, MB, Boobis, L and Bowtell, J (2010) No acetyl group deficit is evident at the onset of exercise at 90% of maximal oxygen uptake in humans. Journal of Sports Sciences. pp. 267-279.

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Abstract

The existence of an acetyl group deficit at or above 90% of maximal oxygen uptake (VO(2max)) has proved controversial, with contradictory results likely relating to limitations in previous research. The purpose of the present study was to determine whether the "acetyl group deficit" occurs at the start of exercise at 90%VO(2max) in a well-controlled study. Eight male participants (age: 33.6 +/- 2.0 years; VO(2max): 3.60 +/- 0.21 litres . min(-1)) completed two exercise bouts at 90%VO(2max) for 3 min following either 30 min of saline (control) or dichloroacetate (50 mg . kg(-1) body mass) infusion, ending 15 min before exercise. Muscle biopsies were obtained immediately before and after exercise while continuous non-invasive measures of pulmonary oxygen uptake and muscle deoxygenation were made. Muscle pyruvate dehydrogenase activity was significantly higher before exercise following dichloroacetate infusion (control: 2.67 +/- 0.98 vs. dichloroacetate: 17.9 +/- 1.1 mmol acetyl-CoA . min(-1) . mg(-1) protein, P = 0.01) and resulted in higher pre- and post-exercise muscle acetylcarnitine (pre-exercise control: 3.3 +/- 0.95 vs. pre-exercise dichloroacetate: 8.0 +/- 0.88 vs. post-exercise control: 11.9 +/- 1.1 vs. post-exercise dichloroacetate: 17.2 +/- 1.1 mmol . kg(-1) dry muscle, P < 0.05). However, substrate-level phosphorylation (control: 125 +/- 20 vs. dichloroacetate: 113 +/- 13 mmol adenosine triphosphate . kg(-1) dry muscle) and VO(2) kinetics (control: 19.2 +/- 2.2 vs. dichloroacetate: 22.8 +/- 2.5 s), were unaltered. Furthermore, dichloroacetate infusion blunted the slow component of VO(2) and muscle deoxygenation and slowed muscle deoxygenation kinetics, possibly by enhancing oxygen delivery during exercise. These data support the hypothesis that the "acetyl group deficit" does not occur at or above 90%VO(2max).

Item Type: Article
Subjects : Nutrition
Divisions : Faculty of Health and Medical Sciences > School of Biosciences and Medicine > Department of Nutritional Sciences
Authors :
AuthorsEmailORCID
Marwood, SUNSPECIFIEDUNSPECIFIED
Constantin-Teodosiou, DUNSPECIFIEDUNSPECIFIED
Casey, EUNSPECIFIEDUNSPECIFIED
Whyte, MBUNSPECIFIEDUNSPECIFIED
Boobis, LUNSPECIFIEDUNSPECIFIED
Bowtell, JUNSPECIFIEDUNSPECIFIED
Date : 18 January 2010
Identification Number : https://doi.org/10.1080/02640410903440884
Depositing User : Symplectic Elements
Date Deposited : 18 Oct 2016 12:51
Last Modified : 18 Oct 2016 12:51
URI: http://epubs.surrey.ac.uk/id/eprint/812483

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