Ketone Supplementation, Glycogen Replenishment and Time Trial Performance Following Glycogen Lowering Exercise

Ketone Supplementation, Glycogen Replenishment and Time Trial Performance Following Glycogen Lowering Exercise

Effect of Ketone Supplementation on Glycogen Replenishment and Time Trial Performance Following Glycogen Lowering Exercise

20 healthy trained males will volunteer to participate in this study. there will be 2 treatments: Carbohydrate- ketone supplementation and carbohydrate alone. The purpose of this study is to evaluate the effect of glucose-ketone supplementation on a 20 km cycling time trial with a 2-hour feeding during a 4-hour recovery period following glycogen depleting exercise.

Carbohydrates (starches & sugars) are important muscle fuel for exercise at moderate to high intensities. Low glycogen content (stored form of carbohydrates in the body) is associated with fatigue. Thus, greater initial glycogen content has been associated with better performance not only in high intensity intermittent sports, but also in prolonged endurance sports. Dose-response studies have determined that ingestion of 1.2 g·kg-1·h-1 of CHO is the appropriate acute recovery dose to optimize glycogen repletion, with no apparent benefit at higher doses. Protein in combination with CHO has also been proposed to enhance glycogen resynthesis when 1 part protein is provided with ~4 parts CHO. Both strategies, optimal CHO intake and CHO in combination with protein for glycogen resynthesis, have resulted in better exercise performance a few hours after a depleting exercise bout. A recent study provided athletes with ketone esters in a drink after glycogen depleting exercise and found that in the presence of high glucose availability, ketone esters increased glycogen stores by 50% compared to a no ketone, high carbohydrate treatment. However, the authors of this study provided a large quantity of carbohydrates intravenously to maintain blood glucose at 10Mm/L. Consequently, it is unknown whether or not ingesting glucose at the optimal dosage would have the same effect. Furthermore, it is unclear whether or not this difference would translate into improved performance in efforts of more moderate duration. Therefore, the purpose of this study is to assess the effect of glucose-ketone supplementation on a 20 km cycling time trial with a 2-hour feeding during a 4-hour recovery period following glycogen depleting exercise.

This will be a double blind repeated measures cross over study. There will be two treatments involved: cabohydrate-ketone supplements and carbohydrates alone (placebo). Participants will complete the protocol twice and the treatment order will be systematically rotated to avoid any order effect. Design of the study is composed of a glycogen depleting exercise session, followed by 4 hours of recovery/supplementation, and a 20 km cycling time trial. All participants will arrive in a fasted state to the laboratory. a glycogen depleting exercise bout will be done followed by a 4 hour recovery period. during this 4 hours, participants will ingest the corresponding treatment for the first 2 hours. after recovery, they will perform a 20 km cycling time trial.

Participants and investigators will be blinded as an individual not involved in the project will assemble and distribute the treatment (drinks) according to a coding system that is kept confidential until the study is completed. Participants will complete the protocol three times and the treatment order will be systematically rotated to avoid any order effect. taste and texture of treatments will be matched and will be distribute in opaque bottles to keep participant blinded

isocaloric carbohydrate - only containing drink will be ingested post glycogen lowering exercise, followed by a 20 km time trial intervention

Ketone - Carbohydrate supplementation will be ingested post glycogen lowering exercise, followed by a 20 km time trial intervention

20 km time trial cycling test will be conducted to measure the effect of different drinks on performance time

Glycogen will be lowered using a 10-min warm-up period at a workload of 50% max wattage power output (Wmax). Thereafter, participants will be instructed to cycle 2-min block periods at alternating workloads of 90% and 50% of Wmax, respectively. This will be continued until the participants are no longer able to complete the 2 min at 90% Wmax. That moment will be defined as the time at which the individual is unable to maintain cycling speed at 60 revolutions/min. At that moment the high-intensity block will be reduced to 80% Wmax. Again, athletes will cycle until they are unable to complete a 2-min block at 80% Wmax, after which the high-intensity block will be reduced to 70% Wmax. Finally, participants will be allowed to stop when pedalling speed could not be maintained at 70% Wmax.

Inclusion Criteria: In order to be eligible to participate in this study you must be a healthy male or female exercise trained individual (at least 1y training experience - at least 3x week), aged 18-40 years. Exclusion Criteria: have not involved been involved in regular exercise (at least 3x week for at least the past year) Have symptoms or take medication for respiratory, cardiovascular, metabolic, neuromuscular disease Use any medications with side effects of dizziness, lack of motor control, or slowed reaction time Are taking part in another research study For women, if you are pregnant or become pregnant during the study. Have a history of concussion/head injuries. Have an excessive alcohol intake (>2 drinks/day) Are a smoker