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Maple Syrup Carbohydrate Dose-Response on 20-km Cycling Time-Trial Performance
Sponsor: Université de Montréal
Summary
The goal of this clinical trial is to learn whether maple syrup can be used as a natural carbohydrate source to help trained male cyclists perform better during long-duration cycling. The study also aims to learn how different amounts of maple syrup affect energy use in the body, stomach comfort, and feelings of effort and fatigue. The main questions the study aims to answer are: * Does consuming more carbohydrate from maple syrup help participants finish a 20-kilometer cycling time trial faster? * How do different amounts of maple syrup change how the body uses carbohydrates and fats during long exercise? * Are higher amounts of maple syrup easy for participants to tolerate without stomach problems? Researchers will compare four drinks: 1. A placebo drink (a look-alike drink with no calories), 2. A drink that provides 60 grams of carbohydrate per hour, 3. A drink that provides 90 grams per hour, and 4. A drink that provides 120 grams per hour. They will compare these drinks to see whether higher carbohydrate amounts lead to better cycling performance and how each dose affects comfort and metabolism. Participants will: * Attend a screening visit that includes a health check and a glucose tolerance test. * Complete a fitness test to measure their aerobic capacity and practice the cycling tests used in the study. * Take part in four separate exercise sessions in random order. Each session includes: * Drinking one of the four study beverages during 2 hours of steady cycling, * Completing two short, all-out 6-second sprints during the ride, * Completing a 20-kilometer cycling time trial as fast as possible, * Reporting stomach symptoms and perceptions of effort, * Providing breath, blood, urine, and sweat samples so researchers can measure how their body uses fuel. All drinks will look, taste, and smell similar so participants cannot tell which one they are receiving. Meals before each session will be provided to keep conditions the same across visits. This study may help athletes and active people choose natural carbohydrate sources that support both performance and comfort during long endurance exercise. The findings may also guide future research on the use of maple syrup as a sports nutrition option.
Official title: Dose-Response Effects of Maple Syrup Carbohydrate Ingestion (60, 90, 120 g/h) on 20-km Cycling Time-Trial Performance, Substrate Oxidation, and Perceptual Responses in Trained Male Cyclists
Key Details
Gender
MALE
Age Range
18 Years - 45 Years
Study Type
INTERVENTIONAL
Enrollment
32
Start Date
2026-02-01
Completion Date
2027-06-01
Last Updated
2026-02-05
Healthy Volunteers
Yes
Interventions
Maple Syrup Beverages
Pure maple syrup is diluted in water and mixed with electrolytes (sodium, potassium, magnesium) to resemble a sports drink. Participants receive one of three carbohydrate doses (60, 90, or 120 g per hour). Drinks are ingested every 15 minutes during 120 minutes of cycling, for a total of \~750 mL per hour. All doses have the same volume, temperature, electrolyte content, and schedule.
placebo beverage
Participants receive a calorie-free electrolyte drink designed to mimic maple syrup. Sotolon (maple aroma) and stevia are added in small amounts to reproduce sweetness, flavor, and smell without providing energy. The drink is administered in identical volumes and timing to the maple syrup beverages (\~750 mL per hour, every 15 minutes).
Pre-Trial Meals
To control nutrition before each trial, participants are provided with a standardized dinner the night before and a standardized breakfast 2-3 hours before testing. Meals contain the same calories and macronutrient distribution across all sessions. Participants must also replicate their training during the previous 48 hours.
D₂O Fluid Absorption
At 30 minutes of cycling, participants ingest a small, safe dose of deuterium oxide (7-8 mL) to measure fluid absorption and gastric emptying. Additional blood samples are collected at +32, +35, and +40 minutes to capture early absorption. Urine is collected to measure deuterium enrichment and validate absorption kinetics.
Time Trial Performance
After 120 minutes of steady cycling, participants complete a 20-km self-paced time trial. Only distance is displayed. The primary outcome is completion time; mean power is analyzed as supportive information.
Substrate Oxidation
Energy metabolism is measured using indirect calorimetry and ¹³C-sucrose breath enrichment. Samples are collected at rest and every 30 minutes during exercise to quantify carbohydrate and fat use, distinguishing ingested vs. stored carbohydrate oxidation. Urine and sweat correct protein oxidation.
Blood Metabolites
Blood samples collected every 30 minutes measure glucose, insulin, lactate, and fatty acids. Samples are stored for later analysis of hormonal and metabolic responses.
Gastrointestinal Symptoms
Participants rate stomach symptoms (0-10 scale) before exercise, every 30 minutes during cycling, and after the time trial. Scores quantify total, upper, and lower GI discomfort.
Perceptual Responses
Effort and muscle pain are assessed using the Borg CR100 scale during exercise and throughout the time trial at preset intervals.
Neuromuscular Fatigue
Participants perform two 6-second maximal sprints at baseline, 60 and 120 minutes of cycling, and after the time trial. Peak power, cadence, and torque assess fatigue progression and recovery.
Hedonic Ratings
Immediately post-exercise, a 0-100 mm scale evaluates sweetness, flavor intensity, and overall liking to assess palatability of each drink.
Blinding Integrity
Bang's Blinding Index is calculated from participant guesses of drink identity to confirm whether blinding was successful.
Locations (1)
Centre EPIC
Montreal, Quebec, Canada