The Effects of Caffeine on Heart Rate and Heart Rate Variability

Not Applicable

• Conditions: Caffeine
• Interventions: Drug: Placebo; Drug: Caffeine

• Registration Number: NCT05521386
• Lead Sponsor: St Mary's University College

Brief 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. 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.

Detailed Description

Not available

Study Timeline

• Status Verified: 2022-08
• Study First Submitted: 2022-08-26
• Study First Submitted QC: 2022-08-26
• Last Update Submitted: 2022-08-26
• Study First Posted: 2022-08-30
• Last Update Posted: 2022-08-30
• Study Start: 2022-09-01
• Primary Completion: 2023-03-31
• Study Completion: 2023-04-30

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: Male
• Target Recruitment: 16

Inclusion Criteria

• Trained cyclists

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Exclusion Criteria

• Injured or a contraindicative medical condition

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo	maltodextrin (placebo) dose of 5 mg per kg of body mass administered orally via a gelatine capsule
Caffeine	Caffeine	caffeine dose of 5 mg per kg of body mass administered orally via a gelatine capsule

Primary Outcome Measures

Name	Time	Method
Heart rate variability	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

Secondary Outcome Measures

Name	Time	Method
Heart rate	From baseline to completion, up to 31 days	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