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

ISRCTN	ISRCTN11339389
DOI	https://doi.org/10.1186/ISRCTN11339389
Protocol serial number	N/A
Sponsor	University of Westminster (UK)
Funders	University of Westminster (UK) - PhD study (self-funded) at the School of Life Sciences, Donations received from:, Whitehorse Nutriceuticals (UK) - Dr Brian Whitton donated caffeine capsules,, Naturally Scientific (UK) - HPLC testing of caffeine levels in espresso coffees by Peter Whitton

Submission date: 17/05/2009
Registration date: 12/08/2009
Last edited: 06/11/2012

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Nervous System Diseases

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Not provided at time of registration

Contact information

Mr Michael McMullen
Scientific

Box 65
Vaddo
76040
Sweden

Email	research@micmcmullen.se

Study information

Primary study design	Interventional
Study design	Crossover, double blind, placebo-controlled, randomised clinical trial
Secondary study design	Randomised controlled trial
Study type	Participant information sheet
Scientific title	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
Study objectives	Coffee and caffeine have/do not have an effect on the autonomic system as measured by changes of cardiac parameters and breathing frequency. This study uses two research models to investigate the short term effects (up to one hour) of coffee and caffeine preparations on the autonomic nerve system and recordings are made of cardiovascular parameters and breathing frequency. The first model involves pre-test recording with post-test recording 30 and 60 minutes after administration. The second model uses continuous recordings for 45 minutes after administration of the test substance. Testing is carried out in supine, sitting and upright postures. The third and fourth models included physiological recordings. Recordings undertaken: 1. Recording of cardiovascular parameters with Finometer-finger pulse contour measures providing measures of blood pressure, heart rate, ejection time, diastolic interval, dp/dt, diastolic pressure time index (DTPI), systolic pressure time index (SPTI), DPTI/SPTI, stroke volume, cardiac output, peripheral resistance, aortic impedance and arterial compliance 2. Recording of breathing frequency with Biopac Respiratory Effort Transducer (TSD201) attached to Finometer 3. R-R (heart beat) recordings with Nerve Express using a Polar thoracic band - used for determining heart rate variability measures
Ethics approval(s)	Approved by the University of Westminster Ethics Committee on the 8th April 2004 (ref: 03/04-08)
Health condition(s) or problem(s) studied	Cardiovascular and autonomic nervous system functioning
Intervention	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. Espresso coffee (16.5 mg caffeine) 4. Espresso coffee and caffeine/placebo capsule The designs of the different models were as follows: Model design 1: Participants were monitored for 90s continuous recordings at 30 minutes and 60 minutes after intervention. The equipment is attached for 15 - 20 minutes each test period and between recording periods the equipment is removed. There are three recording periods per session: pre intervention and post intervention at 30 minutes and 60 minutes. Model design 2: Participants were monitored by a continuous recording which includes pre-intervention recording (baseline) and extends for 35 to 40 minutes after intervention. Continuous recordings of breathing and the cardiovascular system for approximately 45 minutes. The equipment is not removed from the participant during the experimental session. There is only one test period per session. Model design 3: Initially uncontrolled breathing, then alternating frequency (0.167 Hz/0.250 Hz). Recording for 270s in supine and upright postures. Model design 4: Recording for 270s with particpants engaging in four activities (lying, standing, cycling with heart rate: 115 bpm, cycling with heart rate: 135 bpm), presented in the same order for all participants.
Intervention type	Drug
Phase	Not Applicable
Drug / device / biological / vaccine name(s)	Coffee, caffeine
Primary outcome measure(s)	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
Key secondary outcome measure(s)	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
Completion date	01/03/2009

Eligibility

Participant type(s)	Patient
Age group	Adult
Lower age limit	18 Years
Sex	All
Target sample size at registration	105
Key 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
Key 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
Date of first enrolment	01/10/2004
Date of final enrolment	01/03/2009

Locations

Countries of recruitment

United Kingdom
Sweden

Study participating centre

Box 65

Vaddo
76040
Sweden

Results and Publications

Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not provided at time of registration
IPD sharing plan

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article	results	01/04/2011		Yes	No
Results article	results	01/09/2012		Yes	No
Participant information sheet	Participant information sheet	11/11/2025	11/11/2025	No	Yes