Genetic Modifiers of Caffeine Intake and Athletic Performance
Trial Snapshot
- Phase
- Not Applicable
- Sponsor
- University of Toronto
- Enrollment
- 100
- Locations
- 1
- Primary Endpoint
- Efficacy of caffeine to improve power, strength and speed
Study Overview
Brief Summary
Numerous studies have investigated the effect of caffeine on athletic performance, but the findings have not been consistent. This is due, in part, to the differences in response that has been observed both within and between studies. Previous research in our lab has shown that genetic variations affecting caffeine metabolism modify the association between caffeine and heart disease. We hypothesize that the inconsistencies among studies relating caffeine and athletic performance may be due to genetic differences in caffeine metabolism or response. Male athletes will take part in an intervention of caffeine versus placebo, using a randomized double-blinded placebo-controlled design, which will test various exercise protocols (power, strength, anaerobic capacity, endurance) that are associated with performance across multiple sports. We will conduct a genome-wide association study, which is an approach that involves scanning for markers across the genomes of our study participants together, not individuals, to find genetic variations associated with a particular trait such as VO2 max, lactate clearance efficiency, muscle fiber type and changes in exercise performance following caffeine. We will also examine known genetic variations that are associated with caffeine metabolism and response, to determine if these genes also affect response to exercise after ingesting caffeine. Subjects will be paid $50.
Detailed Description
Research Methods and Design
Experimental Design:
This randomized, double-blinded, placebo controlled, within-subjects counter-measured study design will include 100 male athletes from a variety of sports. Females will not be included in this study because hormonal contraceptive use, which is common among female athletes, and the time of the menstrual cycle have a significant effect on caffeine metabolism and exercise test performance measures. Controlling for these factors would require a much larger pool of participants and require considerable resources and time. However, if the findings from the proposed research show promising results in men we would then aim to replicate those findings in female athletes.
Participants will complete 4 visits (~90-120 min each) in the Human Physiology Research Laboratory in the Goldring Center at the University of Toronto. All testing will take place Monday to Saturday at various times. Participants will be instructed to maintain their regular diet (pre-testing meals will be replicated for all visits) and sleeping habits, avoid strenuous activity 48 hours before each visit, and abstain from caffeine one week prior to the first visit and for the duration of the data collection (4 weeks).
Sample Size Calculation
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- Triple (Participant, Investigator, Outcomes Assessor)
Eligibility Criteria
- Ages
- 18 Years to 35 Years (Adult)
- Sex
- Male
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •healthy 18-35 yrs
- •athlete competing/training in given sport 3 or more years
- •currently competing at Varsity, Professional, National level or recreationally but also competing
Exclusion Criteria
- •medical conditions affected by caffeine / avoidance of caffeine
- •injured / not training
- •unable to abstain from caffeine for 4 weeks during study
Arms & Interventions
Caffeine 4 mg
To compare exercise performance of 2 or 4 mg of caffeine per kilogram of body weight to placebo within subjects. Subjects will perform 4 exercise tests.
Intervention: Caffeine 4 mg (Dietary Supplement)
Caffeine 2 mg
To compare exercise performance of 2 or 4 mg of caffeine per kilogram of body weight to placebo within subjects. Subjects will perform 4 exercise tests.
Intervention: Caffeine 2mg (Dietary Supplement)
Caffeine 0 mg
To compare exercise performance of 2 or 4 mg of caffeine per kilogram of body weight to placebo within subjects. Subjects will perform 4 exercise tests.
Intervention: Caffeine 0 (Dietary Supplement)
Outcomes
Primary Outcomes
Efficacy of caffeine to improve power, strength and speed
Time Frame: 2 hours
To determine if their is a positive effect (improvement) effect of 2 or 4 mg of caffeine per kilogram of body mass on four distinct components of fitness: power, strength, anaerobic and aerobic capacity. Therefore, to determine the efficacy of caffeine to shorten time to completion in time trial, and increase power/strength in wingate, vertical jump and handgrip tests.
Secondary Outcomes
- Individual genotypes, caffeine ingestion and athletic performance(1 day)
Investigators
Ahmed El-Sohemy
Associate Professor
University of Toronto