The Effects of Exogenous Ketosis on Ultra-endurance Recovery and Performance

Not Applicable

Recruiting

• Conditions: Exogenous Ketosis; Endurance Cycling Performance; Fatigue; Muscle, Heart; Fatigue, Mental

• Registration Number: NCT06965491
• Lead Sponsor: KU Leuven

Brief Summary

The study aims to investigate the effects of post-exercise and pre-sleep ketosis via oral ketone ester supplementation on physical and mental recovery during a multi-day cycling stage race.

Detailed Description

Ultra-endurance events are becoming increasing popular. Participation in the multi-day events adds a lot of physical and mental strain on the body, while the athletes are still required to perform. Without appropriate recovery the athletes are at increased risk of overreaching, injury, or illness.

Therefore, the purpose of the study is to create a better understanding of the exercise fatigue experienced during ultra-endurance performance and the role intermittent exogenous ketosis (IEK) plays in reducing the amount of fatigue to maintain performance during multi-day racing and lower the risk of injury and illness.

Participants will first compete in a 8-day simulated stage race performed on taxc trainers and then we will conduct a field study during the Absa Cape Epic a 8-day mountain bike stage race. Immediately following each stage and 30-mins before bed the participants will consume either a ketone ester and taste-match placebo drink. During the race the following variables will be measured; hydration status, weight change, activity readiness, and nutrition intake. Cognitive function will be assessed on day 2, 4 and 8 of racing. One day before and one day after the race the participants will report to the lab to assess basal metabolic rate, stress via questionnaires, appetite, cognitive function, muscle biopsies, venous blood samples, mechanical efficiency and 30-min Time Trial.

Study Timeline

• Study Start: 2024-03-01
• Study First Submitted: 2024-10-04
• Primary Completion: 2025-03-27
• Status Verified: 2025-05
• Study First Submitted QC: 2025-05-01
• Last Update Submitted: 2025-05-01
• Study First Posted: 2025-05-11
• Last Update Posted: 2025-05-11
• Study Completion: 2025-10-30

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 24

Inclusion Criteria

• have been cycling consistently for at least 1 year before entry into the study
• have been cycling for a minimum of 7 hours per week for the 6 months leading up to the study
• additional for the field study: valid entry to the 2025 edition of the Absa Cape Epic
• non-smoker

Exclusion Criteria

• Do not follow a ketogenic diet or low-carbohydrate diet
• Have any metabolic or auto-immune disease that will influence their metabolism
• Take medication or supplements that is known to affect ketone supplement metabolism
• suffering from a recurring injury or illness from which they have not fully recovered that is a contr-indication to perform high-intensity exercise
• Unable to finish each stage
• Women: if they are pregnant or breastfeeding

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Muscle soreness	During the intervention	Visual analog scale (0-10) How sore does you leg muscles feel? The VAS was used as a subjective measure of muscle soreness
Sleep: Non-REM	1 week prior to racing and during the race	The Fitbit Inspire 3 will be used to determine the NON-REM sleep phase for each night in minutes
Sleep: WASO	1 week prior to racing and during the race	The FITBIT inspire 3 will be used to measure wake after sleep onset in minutes for each night
Hydration status	Baseline, During the intervention and 1 day after the intervention	Before every stage, the participants provided a urine sample in a cup. A urine-specific refractometer (Atago) was used to determine their hydration status
Cognitive function: reaction time	Pre-intervention, day 2, 4 and 8 of the intervention	CANTAB test battery reaction time test was used to determine reaction time in milliseconds.
Cognitive function: rapid visual processing	Pre-intervention, day 2, 4 and 8 of the intervention	CANTAB test battery rapid visual processing test was used to assess their susceptibility to false alarms
Cognitive function: swm	Pre-intervention, day 2, 4 and 8 of the intervention	CANTAB spatial working memory test was used to access executive function; the main outcome measure used was the number of errors
Sleep: REM	1 week prior to racing and during the race	The Fitbit Inspire 3 was used to measure the total duration of rapid eye motion (REM)sleep during each night for the duration of the study. The REM sleep phase will be analysed in minutes
Physical stress	pre-intervention and 1 day after the intervention	RESTQ-76 sport questionnaire was used to assess the stress-recovery balance
Sleep Duration	1 week prior to racing and during the race	Fitbit inspire 3 was used to measure sleep duration (hours:minutes:seconds)

Secondary Outcome Measures

Name	Time	Method
Mechanical efficiency	pre-intervention and 1 day after the intervention	Mechanical efficiency will be determined during three constant load (100 watts, 150 watts, and 200 watts) cycling bouts of 5 minutes on a calibrated ergometer (Avantronic Cyclus II). Throughout the test, gas exchange will continuously be measured using calibrated metabolic analyzer with a face mask (Cortex, Metalyzer IIIb). VO2 and VCO2 data of the final minute of each workload will be used to calculate gross efficiency (%).
Time trial performance	pre-intervention and 1 day after the intervention	The participants will perform a 30-minute time trial. The average power output (watts) achieved will be used as the outcome measure.
Appetite	pre-intervention, during the intervention, 1 day after the intervention	Appetite will be assessed with a Likert visual analog scale (0-10) using the following four questions: "How hungry do you feel?" "How full do you feel?" "How satisfied do you feel?" "How much do you think you could eat now?"
Macronutrient intake	baseline, during the intervention	Participants will complete a food diary using the Mijnetemeter application on their phone. Total fat, protein and carbohydrate intake will be determined in grams for each day.
Total energy intake	baseline, during the intervention	Participants will complete a food diary, using the Mijnetemeter application on their phones. total energy intake (kilojoules) will be calculated for each day.
Racing intensity	during each stage	hear rate zones during racing
Body weight change	During the intervention	Body mass was measured using a SECA, model 813 electrical scale, before and after each stage as a secondary method to assess hydration status. Body mass was measured to the nearest 0.1 kilogram

Trial Locations

Locations (1)

KU Leuven; 🇧🇪 Leuven, Vlaams-Brabant, Belgium