The short term effects of coffee and caffeine on the cardiovascular and autonomic nervous systems

The short term effects of coffee and caffeine on the cardiovascular and autonomic nervous systems: a crossover, double blind, placebo-controlled and cohort randomised clinical trial

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN11339389

Enrollment

105

Registered

2009-08-12

Start date

2004-10-01

Completion date

Unknown

Last updated

2015-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Cardiovascular and autonomic nervous system functioning Nervous System Diseases Autonomic nervous system

Interventions

Each model was conducted over time and only one model was recruited for at a time. All models were crossover. Patients will be randomised to: 1. Placebo capsule 2. Caffeine capsule (67, 133, 200 mg) 3

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. Voluntary recruits from the students, staff and associates of the University of Westminster 2. Non-medicated 3. Normotensive 4. Aged 18 to 63 years, either sex 5. Habitual caffeine users (consumption of tea or coffee on a daily basis) or non caffeine users (less than 3 servings per week) Model 4 only: 6. Regular cyclists

Exclusion criteria

Exclusion criteria: 1. Pregnant and breast feeding women 2. Hypertensive (blood pressure greater than 140/90 mmHg) 3. Users of prescribed medicines For models 1 and 2: 4. Smokers

Design outcomes

Primary

Measure	Time frame
Pre-planned comparisons to placebo conditions: 1. The cardiovascular parameters derived from the Finometer recordings of the finger pulse contour (www.finapres.com): systolic, diastolic and mean blood pressure, heart rate, ejection time, diastolic interval, dp/dt, DPTI, SPTI, DPTI/SPTI, ejection time, stroke volume, cardiac output, total peripheral resistance, aortic impedance and arterial compliance 2. Breathing rate Timepoints: Model 1: recording 30 and 60 minutes after intervention; test session 15 minutes Model 2: constant recording for 40 minutes after intervention	—

Measure

Time frame

Pre-planned comparisons to placebo conditions: 1. The cardiovascular parameters derived from the Finometer recordings of the finger pulse contour (www.finapres.com): systolic, diastolic and mean blood pressure, heart rate, ejection time, diastolic interval, dp/dt, DPTI, SPTI, DPTI/SPTI, ejection time, stroke volume, cardiac output, total peripheral resistance, aortic impedance and arterial compliance 2. Breathing rate Timepoints: Model 1: recording 30 and 60 minutes after intervention; test session 15 minutes Model 2: constant recording for 40 minutes after intervention

—

Secondary

Measure	Time frame
1. Pre planned comparisons of intervention effects in different postures 2. Variability analysis of Finometer derived cardiovascular parameters as appropriate in a post experimental analysis 3. Dosage relationships Timepoints: Model 1: recording 30 and 60 minutes after intervention; test session 15 minutes Model 2: constant recording for 40 minutes after intervention	—

Countries

United Kingdom

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 4, 2026