Diet can alter blood ketone levels and this in turn may affect exercise capacity. This study will determine if the acute ingestion of a ketone supplement alters cycling exercise efficiency. Participants will perform three trials in a randomized order. Each trial will involve an incremental exercise protocol on a stationary cycle ergometer to volitional fatigue. Participants will ingest either a high or low dose of a ketone supplement or a taste-matched placebo drink prior to exercise. Blood samples will be obtained to assess selected metabolic responses. This study will provide information regarding the effect of ketone supplementation on exercise efficiency.
This study will determine if the acute ingestion of a ketone supplement alters cycling exercise efficiency. Trained participants with cycling experience will be recruited. Participants will perform three trials in a randomized order. Each trial will involve a 3-minute warm-up followed by an incremental ramp test. The ramp will initially consist of three, 5-minute stages performed at relative workloads corresponding to 75%, 100%, and 125% of individual ventilatory threshold intensity. This will be followed by a further incremental ramp test to volitional fatigue. Participants will ingest either a high or low dose of a ketone supplement or a taste-matched placebo drink prior to exercise using a randomized, double-blind crossover design. Diet prior to exercise will be standardized between trials for a given participant. Blood samples will be obtained to assess selected metabolic responses. This study will provide information regarding the effect of ketone supplementation on exercise efficiency.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
34
A commercial liquid ketone monoester supplement.
A liquid placebo that is taste-matched to the ketone monoester supplement.
McMaster University
Hamilton, Ontario, Canada
Exercise efficiency
Power output expressed relative to pulmonary oxygen uptake to determine cycling economy in watt per litre of oxygen per minute
Time frame: Continuous measurement made over each of three, 5-minute consecutive stages of an incremental cycle exercise test at relative workloads corresponding to 75%, 100%, and 125% of individual ventilatory threshold intensity
Heart rate
Mean heart rate
Time frame: Continuous measurement made over each of three, 5-minute consecutive stages of an incremental cycle exercise test at relative workloads corresponding to 75%, 100%, and 125% of individual ventilatory threshold intensity
Rating of perceived exertion
Rating of perceived exertion measured using a 6-20 scale
Time frame: Measurement made at the end of each of three, 5-minute consecutive stages of an incremental cycle exercise test at relative workloads corresponding to 75%, 100%, and 125% of individual ventilatory threshold intensity
Ketone body content in venous blood
Mixed venous blood content of the ketone body beta-hydroxybutyrate
Time frame: Measurement made immediately prior to exercise
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