The Repeatability of the Effect of Caffeine Supplementation on Submaximal Physiological Responses and Cycling Time Trial Performance

NCT06935214 | Not Yet Recruiting

• 1 other identifier: SMU_ETHICS_2024-25_992
• Study Type: interventional
• Target: 12
• Locations: 0 countries
• Sites: N/A

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.

Conditions

Caffeine

Keywords

caffeine; genetics; cycling; time trial

Outcome Measures

Primary Outcomes (5)

• Blood lactate concentration

  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

  From baseline to completion, up to 31 days

• Heart rate

  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.

  From baseline to completion, up to 31 days

• Oxygen uptake

  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

  From baseline to completion, up to 31 days

• Perceived exertion

  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

  From baseline to completion, up to 31 days

• Time trial completion time

  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.

  From baseline to completion, up to 31 days

Study Arms (2)

Caffeine

EXPERIMENTAL

5 mg/kg dose of caffeine (in pill form) - Trial 1

Dietary Supplement: Caffeine

Placebo

PLACEBO COMPARATOR

5 mg/kg dose of placebo (Maltodextrin in pill form) - Trial 2

Dietary Supplement: Placebo

Interventions

Caffeine DIETARY_SUPPLEMENT

5 mg/kg of caffeine in pill form

Caffeine

Placebo DIETARY_SUPPLEMENT

5 mg/kg dose of maltodextrin in pill form

Placebo

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

Sponsors & Collaborators

• St. Mary's University, Twickenham: lead

MeSH Terms

Interventions

Caffeine

Intervention Hierarchy (Ancestors)

Xanthines; Alkaloids; Heterocyclic Compounds; Purinones; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 11, 2025
• First Posted: April 20, 2025
• Study Start: May 1, 2025
• Primary Completion: August 23, 2025
• Study Completion: December 31, 2025
• Last Updated: April 20, 2025

Record last verified: 2025-04