Condition category
Nervous System Diseases
Date applied
17/05/2009
Date assigned
12/08/2009
Last edited
06/11/2012
Prospective/Retrospective
Retrospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information

Type

Scientific

Primary contact

Mr Michael McMullen

ORCID ID

Contact details

Box 65
Vaddo
76040
Sweden
research@micmcmullen.se

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

N/A

Study information

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

Acronym

Study hypothesis

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

Approved by the University of Westminster Ethics Committee on the 8th April 2004 (ref: 03/04-08)

Study design

Crossover, double blind, placebo-controlled, randomised clinical trial

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Not specified

Trial type

Treatment

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

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 names

Coffee, caffeine

Primary outcome measures

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 outcome measures

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

Overall trial start date

01/10/2004

Overall trial end date

01/03/2009

Reason abandoned

Eligibility

Participant 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

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

105 participants

Participant 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

Recruitment start date

01/10/2004

Recruitment end date

01/03/2009

Locations

Countries of recruitment

United Kingdom

Trial participating centre

Box 65
Vaddo
76040
Sweden

Sponsor information

Organisation

University of Westminster (UK)

Sponsor details

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

Sponsor type

University/education

Website

http://www.wmin.ac.uk/

Funders

Funder type

University/education

Funder name

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

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Funder name

Donations received from:

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Funder name

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

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Funder name

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

Alternative name(s)

Funding Body Type

Funding Body Subtype

Location

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

1. 2011 results in http://www.ncbi.nlm.nih.gov/pubmed/21779579
2. 2012 results in http://www.ncbi.nlm.nih.gov/pubmed/22614720

Publication citations

  1. Results

    McMullen MK, Whitehouse JM, Shine G, Towell A, Habitual coffee and tea drinkers experienced increases in blood pressure after consuming low to moderate doses of caffeine; these increases were larger upright than in the supine posture., Food Funct, 2011, 2, 3-4, 197-203, doi: 10.1039/c0fo00166j.

  2. Results

    McMullen MK, Whitehouse JM, Shine G, Whitton PA, Towell A, Caffeine in hot drinks elicits cephalic phase responses involving cardiac activity., Food Funct, 2012, 3, 9, 931-940, doi: 10.1039/c2fo00002d.

Additional files

Editorial Notes