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 measure
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 (if study stopped)
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
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
Basic results (scientific)
Publication list
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
-
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.
-
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.