Does Dietary Nitrate Supplementation Attenuate the Cardiovascular Strain Elicited by Caffeine and Cold Exposure in Healthy Individuals?
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Loughborough University
- Enrollment
- 24
- Locations
- 2
- Primary Endpoint
- Brachial blood pressure
Study Overview
Brief Summary
Dietary inorganic nitrate supplementation may have positive implications on cardiovascular function. The aim of this project is to determine if nitrate supplementation can attenuate the effects that caffeine and cold exposure have on the cardiovascular system.
Detailed Description
Acute caffeine consumption and cold exposure elicit negative effects on the cardiovascular system. Humans are regularly exposed to such conditions of increased cardiovascular strain, which may lead to elevated chronic cardiovascular risk. On the other hand, dietary inorganic nitrate supplementation is well established to improve cardiovascular function in healthy individuals. Thus, acute nitrate supplementation may compensate for the negative effects that caffeine and the cold place on the cardiovascular system. These effects will be measured using peripheral blood pressure, pulse wave analysis, heart rate variability, forearm blood flow, flow mediated dilation, and blood and saliva markers.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Prevention
- Masking
- Double (Participant, Investigator)
Masking Description
Double-blinded using supplement placebos.
Eligibility Criteria
- Ages
- 18 Years to 40 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Blood pressure < 130 mmHg systolic and < 85 mmHg diastolic. BMI between 18.5 and 29.9 kg/m
- •Females must be naturally menstruating (regular length cycle and menses) or using a form of combined hormonal contraception (for at least 6 months).
Exclusion Criteria
- •Existing cardiovascular or metabolic conditions. Experience any adverse reactions to experimental procedures or supplements. Allergies to supplements or breakfast items. Involved in any other studies. Blood pressure > 130 mmHg systolic and > 85 mmHg diastolic.
Outcomes
Primary Outcomes
Brachial blood pressure
Time Frame: Mean of 5 readings taken pre-supplementation (0 hours) and post-supplementation (2.5 hours). 1 reading was taken pre- cold pressor test (3.5 hours). All measures were recorded on every experimental trial (4 trials with at least 48 h washout between).
Brachial blood pressure was collected using an automatic sphygmomanometer.
Flow mediated dilation
Time Frame: Measured pre-supplementation (at 0 hours) and post-supplementation (at 2.5 hours) for every experimental trial (4 trials with at least 48 h washout between).
Baseline diameter, peak diameter, change in diameter, and shear stimulus following flow mediated dilation procedure of the brachial artery with post-occlusion reactive hyperaemia.
Central blood pressure and pulse wave variables
Time Frame: Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and during the cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between).
Mean of 2-3 readings for aortic systolic BP, aortic diastolic BP, HR, Augmentation index, augmentation index corrected to HR of 75 bpm, pulse pressure, and augmentation pressure.
Secondary Outcomes
- Forearm blood flow(Measured pre-supplementation (at 0 hours) and post-supplementation (at 2.5 hours) for every experimental trial (4 trials with at least 48 h washout between).)
- Salivary nitrate and nitrite(Measured pre-supplementation (at 0 hours) and post-supplementation (at 2.5 hours) for every experimental trial (4 trials with at least 48 h washout between).)
- Heart rate variability(Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and during the cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between).)
- NIBP continuous blood pressure(Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and during the cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between).)
- Whole blood RSNO(Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and immediately post- cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between).)
- Plasma nitrate, nitrite, cGMP(Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and immediately post- cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between))
Investigators
Stephen Bailey
Principal Investigator
Loughborough University