Caffeine
Conditions
Brief summary
The goal of this clinical trial is to learn about the effects of caffeine on exercise physiology and the subsequent quantification of athlete training zones in trained cyclists. The main questions that it aims to answer are: * What are the effects of low and moderate doses of caffeine on exercise physiology. * How do the effects of caffeine on exercise physiology affect the calculation of training zones. * Do the effects of caffeine on exercise physiology differ between men and women. Participants will complete four trials on a cycle ergometer as follows: * Trial 1: participants will complete two incremental tests to determine the power outputs required to elicit 50-80% of maximal oxygen consumption for trials 2-4. * Trials 2-4: participants will consume (in a randomized order) either a low (2 mg/kg) dose of caffeine, a moderate (5 mg/kg) dose of caffeine, or a placebo (maltodextrin), 45 minutes prior to to completing an incremental cycling test from 50-80% of maximal oxygen uptake. Measures of heart rate, oxygen uptake, blood lactate, and perceived exertion will be recorded throughout all trials. Researchers will compare the effects of exercise intensity, caffeine dose, and sex to see if they affect exercise physiology and training zone quantification.
Interventions
DRUGLow caffeine dose
2 mg/kg dose of caffeine in pill form
DRUGModerate caffeine dose
5 mg/kg dose of caffeine in pill form
DRUGPlacebo
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
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* To be considered for inclusion in the study, participants must be regular cyclists, between 18 and 45 years of age, capable of completing a 20 km cycling time trial at a minimum speed of 30 km/h for men and 28 km/h for women (arbitrary inclusion criteria to ensure a sufficient standard of athlete). Female participants must have a regular menstrual cycle and not be taking oral contraceptives.
Exclusion criteria
\-
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Blood lactate concentration | From baseline to completion, up to 31 days | Change from baseline in blood lactate concentration measured at rest and at seven different exercise intensities (50, 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 (50, 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 (50, 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 (50, 55, 60, 65, 70, 75, and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer |
Outcome results
None listed