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

ISRCTN ISRCTN11339389
DOI https://doi.org/10.1186/ISRCTN11339389
Secondary identifying numbers N/A
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

Study designCrossover, double blind, placebo-controlled, randomised clinical trial
Primary study designInterventional
Secondary study designRandomised controlled trial
Study setting(s)Not specified
Study typeTreatment
Participant information sheet Not available in web format, please use the contact details below to request a patient information sheet
Scientific titleThe 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 objectivesCoffee 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) studiedCardiovascular and autonomic nervous system functioning
InterventionEach 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 typeDrug
Pharmaceutical study type(s)
PhaseNot Applicable
Drug / device / biological / vaccine name(s)Coffee, caffeine
Primary outcome measurePre-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 outcome measures1. 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
Overall study start date01/10/2004
Completion date01/03/2009

Eligibility

Participant type(s)Patient
Age groupAdult
Lower age limit18 Years
SexBoth
Target number of participants105 participants
Key inclusion criteria1. 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 criteria1. 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 enrolment01/10/2004
Date of final enrolment01/03/2009

Locations

Countries of recruitment

  • Sweden
  • United Kingdom

Study participating centre

Box 65
Vaddo
76040
Sweden

Sponsor information

University of Westminster (UK)
University/education

c/o Dr Julie Whitehouse
School of Life Sciences
115 New Cavendish Street
London
W1W 6UW
England
United Kingdom

Website http://www.wmin.ac.uk/
ROR logo "ROR" https://ror.org/04ycpbx82

Funders

Funder type

University/education

University of Westminster (UK) - PhD study (self-funded) at the School of Life Sciences

No information available

Donations received from:

No information available

Whitehorse Nutriceuticals (UK) - Dr Brian Whitton donated caffeine capsules,

No information available

Naturally Scientific (UK) - HPLC testing of caffeine levels in espresso coffees by Peter Whitton

No information available

Results and Publications

Intention to publish date
Individual participant data (IPD) Intention to shareNo
IPD sharing plan summaryNot provided at time of registration
Publication and dissemination planNot 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