Caffeine
Conditions
Keywords
caffeine, genetics, cycling, time trial
Brief summary
Recently, Grgic (2018) discussed the concept of responders and non-responders to caffeine supplementation highlighting the importance of the repeatability of results. However, the number of studies that have investigated this idea by repeating the same time-trial performance test multiple times with the same caffeine dose is sparse (Astorino et al., 2012; Del Coso et al., 2019). Furthermore, studies have shown that differences in the CYP1A2 genotype may account for some of the variation in time-trial performance (Guest et al., 2018). Thus, the current study aims to identify whether the effects of moderate caffeine supplementation (5 mg/kg) on time-trial performance are repeatable to aid the identification of responders and non-responders. Additionally, the study aims to determine if the CYP1A2 genotype may explain any of the variability in time-trial performance in trained male cyclists.
Interventions
DIETARY_SUPPLEMENTCaffeine
5 mg/kg of caffeine in pill form
DIETARY_SUPPLEMENTPlacebo
5 mg/kg dose of maltodextrin in pill form
Sponsors
St. Mary's University, Twickenham
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
MALE
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* To be considered for inclusion in the study, participants must be regular cyclists, between 18 and 35 years of age, capable of completing a 20 km cycling time trial at a minimum speed of 30 km/h (arbitrary inclusion criteria to ensure a sufficient standard of athlete).
Exclusion criteria
\-
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Blood lactate concentration | From baseline to completion, up to 31 days | Description: Change from baseline in blood lactate concentration measured at rest and at six different exercise intensities (55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer |
| Heart rate | From baseline to completion, up to 31 days | Change from baseline in heart rate measured at rest and at seven different exercise intensities (55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer. |
| Oxygen uptake | From baseline to completion, up to 31 days | Change from baseline in oxygen uptake measured at rest and at seven different exercise intensities (55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer |
| Perceived exertion | From baseline to completion, up to 31 days | Change from baseline in rating of perceived exertion measured (using the 6-20 Borg scale) at seven different exercise intensities (55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer |
| Time trial completion time | From baseline to completion, up to 31 days | Change from baseline in time to complete a time trial at a target amount of work on an electromagnetically-braked cycle ergometer calculated from the power output at maximal oxygen uptake and designed to last approximately 25 minutes. |
Outcome results
None listed