CaffeineNCT05521386
The Effects of Caffeine on Heart Rate and Heart Rate Variability
A study testing Caffeine in people with Caffeine, run by St Mary's University College.
Trial summary
In previous research we have shown that an acute caffeine dose of 5 mg/kg body mass reduces heart rate at rest and during low intensity exercise, with the effect dissipating as exercise intensity increases. Read more about this study
- Who is it for?
- Ages 18 to 55 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Caffeine
- What is being tested?
- Caffeine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 16 participants
- Where
- No sites listed yet
- Study dates
- 1 Sep 2022to 30 Apr 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Trained cyclists
Who cannot join
- Injured or a contraindicative medical condition
About this study
Official title: The Effects of Caffeine Supplementation on Heart Rate and Heart Rate Variability at Rest and During Submaximal Exercise
In previous research we have shown that an acute caffeine dose of 5 mg/kg body mass reduces heart rate at rest and during low intensity exercise, with the effect dissipating as exercise intensity increases. If, as suspected, the effect at rest and at low intensities is due to an effect of caffeine on parasympathetic activity, this is likely to be reflected in an increase in heart rate variability (the beat-to-beat fluctuation in heart rate). The aim of this study is therefore to investigate the effect of caffeine on heart rate and heart rate variability at rest and during submaximal exercise.
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CaffeineDrug
Single pill in an acute dose of 5 mg per kg of body mass
PlaceboDrug
Single pill in an acute dose of 5 mg per kg of body mass
| Study group | Role | What they receive |
|---|---|---|
| Caffeine | Experimental | caffeine dose of 5 mg per kg of body mass administered orally via a gelatine capsule Receives: Drug: Caffeine |
| Placebo | Placebo comparator | maltodextrin (placebo) dose of 5 mg per kg of body mass administered orally via a gelatine capsule Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Heart rate variability
Change from baseline in heart rate variability measured at rest and at five different exercise intensities (40, 50, 60, 70 and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer
Measured: From baseline to completion, up to 31 days
Secondary outcomes (1)
Heart rate
Change from baseline in heart rate measured at rest and at five different exercise intensities (40, 50, 60, 70 and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer
Measured: From baseline to completion, up to 31 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Aug 2022
- Study start1 Sep 2022 (estimated)
- Primary completion31 Mar 2023 (estimated)
- Study completion30 Apr 2023 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for CaffeineStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 16 participants (estimated)
Sponsor and investigators
- Lead sponsor
- St Mary's University College
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05521386
- Sponsor's protocol ID
- StMarysUC5
- Status last verified
- Aug 2022
- First submitted
- 26 Aug 2022
- Last updated
- 30 Aug 2022
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Glaister M, Lythgoe D, Kamath S. The Effects of Caffeine on Heart Rate and Heart Rate Variability at Rest and During Submaximal Cycling Exercise. Res Q Exerc Sport. 2025 Mar;96(1):155-163. doi: 10.1080/02701367.2024.2377303. Epub 2024 Jul 15.
PubMed 39008947
Study at a glance
From the registry record, last updated by the sponsor on 30 Aug 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Caffeine Supplementation on Heart Rate and Heart Rate Variability at Rest and During Submaximal Exercise
- ClinicalTrials.gov ID
- NCT05521386
- Acronym / sponsor ID
- StMarysUC5
- Conditions
- Caffeine
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 16 participants (estimated)
- Lead sponsor
- St Mary's University CollegeUniversity, hospital or other
- Study start
- 1 Sep 2022 (estimated)
- Primary completion
- 31 Mar 2023 (estimated)
- Study completion
- 30 Apr 2023 (estimated)
- First posted
- 30 Aug 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
In previous research we have shown that an acute caffeine dose of 5 mg/kg body mass reduces heart rate at rest and during low intensity exercise, with the effect dissipating as exercise intensity increases. If, as suspected, the effect at rest and at low intensities is due to an effect of caffeine on parasympathetic activity, this is likely to be reflected in an increase in heart rate variability (the beat-to-beat fluctuation in heart rate). The aim of this study is therefore to investigate the effect of caffeine on heart rate and heart rate variability at rest and during submaximal exercise.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Caffeine | Experimental | Drug: Caffeinecaffeine dose of 5 mg per kg of body mass administered orally via a gelatine capsule |
| Placebo | Placebo comparator | Drug: Placebomaltodextrin (placebo) dose of 5 mg per kg of body mass administered orally via a gelatine capsule |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Trained cyclists
Key exclusion criteria (1 listed)
- Injured or a contraindicative medical condition
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CaffeineSingle pill in an acute dose of 5 mg per kg of body mass | Drug | Caffeine |
| PlaceboSingle pill in an acute dose of 5 mg per kg of body mass | Drug | Placebo |
Primary outcome
Heart rate variability
Time frame: From baseline to completion, up to 31 days
Change from baseline in heart rate variability measured at rest and at five different exercise intensities (40, 50, 60, 70 and 80% percent of maximal oxygen uptake) on an electromagnetically-braked cycle ergometer
1 secondary outcome
Heart rate
Time frame: From baseline to completion, up to 31 days
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Aug 2022.
- Derived from this study: PubMed 39008947Glaister M, Lythgoe D, Kamath S. The Effects of Caffeine on Heart Rate and Heart Rate Variability at Rest and During Submaximal Cycling Exercise. Res Q Exerc Sport. 2025 Mar;96(1):155-163. doi: 10.1080/02701367.2024.2377303. Epub 2024 Jul 15.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
A study testing Caffeine in people with Caffeine, run by St Mary's University College.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 30 Aug 2022. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Heart rate variability (time frame: From baseline to completion, up to 31 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05521386, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Aug 2022.