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. 2017 Oct 23;8:806.
doi: 10.3389/fphys.2017.00806. eCollection 2017.

Ketone Diester Ingestion Impairs Time-Trial Performance in Professional Cyclists

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Free PMC article

Ketone Diester Ingestion Impairs Time-Trial Performance in Professional Cyclists

Jill J Leckey et al. Front Physiol. .
Free PMC article

Abstract

We investigated the effect of pre- "race" ingestion of a 1,3-butanediol acetoacetate diester on blood ketone concentration, substrate metabolism and performance of a cycling time trial (TT) in professional cyclists. In a randomized cross-over design, 10 elite male cyclists completed a ~31 km laboratory-based TT on a cycling ergometer programmed to simulate the 2017 World Road Cycling Championships course. Cyclists consumed a standardized meal [2 g/kg body mass (BM) carbohydrate (CHO)] the evening prior to a trial day and a CHO breakfast (2 g/kg BM CHO) with 200 mg caffeine on the morning of a trial day. Cyclists were randomized to consume either the ketone diester (2 × 250 mg/kg) or a placebo drink, followed immediately by 200 mL diet cola, given ~ 30 min before and immediately prior to commencing a 20 min incremental warm-up. Blood samples were collected prior to and during the warm-up, pre- and post- TT and at regular intervals after the TT. Urine samples were collected pre- and post- warm-up, immediately post TT and 60 min post TT. Pre-exercise ingestion of the diester resulted in a 2 ± 1% impairment in TT performance that was associated with gut discomfort and higher perception of effort. Serum β-hydroxybutyrate, serum acetoacetate, and urine ketone concentrations increased from rest following ketone ingestion and were higher than placebo throughout the trial. Ketone ingestion induces hyperketonemia in elite professional cyclists when in a carbohydrate fed state, and impairs performance of a cycling TT lasting ~50 min.

Keywords: cycling; ketone ester; ketones; performance; time-trial.

Figures

Figure 1
Figure 1
Overview of study design.
Figure 2
Figure 2
Mean and individual TT performance time (A) and mean power output (B) following exogenous KET or PLAC ingestion. Values are mean ± SD. *KET different to PLAC.
Figure 3
Figure 3
Course profile of World Championships TT course (Bergen, Norway) (A), average power output (B), cadence (C), and heart rate (D) during TT as a percentage of total distance, following exogenous KET or PLAC ingestion. Values are mean ± SD. a different to 5% in KET; b different to 5% in PLAC; c different to 10% in KET; d different to 10% in KET; *KET different to PLAC, e different to all other time points in KET, 50% different to f.
Figure 4
Figure 4
Serum FFA (A), βHB (B), and AcAc (C) concentrations following exogenous KET or PLAC ingestion whilst completing a cycling TT. Values are mean ± SD. Tx1 and Tx2 refer to dose one and two of KET or PLAC drink. *KET different to PLAC at time point; a different to t = 0 min within KET; b different to t = 0 min within PLAC.
Figure 5
Figure 5
Urine ketone (A) and blood βHB (B) concentrations following exogenous KET or PLAC ingestion whilst completing a cycling TT. Values are mean ± SD. Tx1 and Tx2 refer to dose one and two of KET or PLAC drink, w/up refers to warm-up. *KET different to PLC at time point; a different to t = 0 min within KET.
Figure 6
Figure 6
Blood glucose (A) and lactate (B) concentrations following exogenous KET or PLAC ingestion whilst completing a cycling TT. Values are mean ± SD. Tx1 and Tx2 refer to dose one and two of KET or PLAC drink. *KET different to PLAC at time point; a different to t = 120 min within KET; b different to t = 120 min within PLAC; c different to 95 min within and PLAC; #different to all other time points within PLAC; $different to all other time points within KET.

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