The Effects of Nitrate, Caffeine, and Cold Exposure on Cardiovascular Function.

NCT06602921 | Completed

• 1 other identifier: LoughboroughUAM
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

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.

Conditions

Nitrate; Caffeine; Cold Exposure

Keywords

Cardiovascular Function; Flow mediated dilation

Outcome Measures

Primary Outcomes (3)

• Brachial blood pressure

  Brachial blood pressure was collected using an automatic sphygmomanometer.

  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).

• Flow mediated dilation

  Baseline diameter, peak diameter, change in diameter, and shear stimulus following flow mediated dilation procedure of the brachial artery with post-occlusion reactive hyperaemia.

  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).

• Central blood pressure and pulse wave variables

  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.

  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).

Secondary Outcomes (6)

• 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).

Study Arms (4)

Nitrate, caffeine, and cold pressor test (CPT)

EXPERIMENTAL

All outcome variables will be measured for 24 participants in a trial where they receive 400 mg nitrate in the form of beetroot extract, 6 mg/kg caffeine powder, and undergo a 3 min cold pressor test.

Dietary Supplement: TruBeet inorganic beetroot juice; Dietary Supplement: Caffeine; Other: Cold pressor test

Nitrate, placebo caffeine, and CPT

PLACEBO COMPARATOR

All outcome variables will be measured for 24 participants in a trial where they receive 400 mg nitrate in the form of beetroot extract, 6 mg/kg cornflour (caffeine placebo), and undergo a 3 min cold pressor test.

Dietary Supplement: TruBeet inorganic beetroot juice; Other: Cold pressor test

Placebo nitrate, caffeine, and CPT

PLACEBO COMPARATOR

All outcome variables will be measured for 24 participants in a trial where they receive nitrate-depleted beetroot extract (placebo), 6 mg/kg caffeine powder, and undergo a 3 min cold pressor test.

Dietary Supplement: Caffeine; Other: Cold pressor test

Placebo nitrate, placebo caffeine, and CPT

PLACEBO COMPARATOR

All outcome variables will be measured for 24 participants in a trial where they receive nitrate-depleted beetroot extract (placebo), 6 mg/kg cornflour (caffeine placebo), and undergo a 3 min cold pressor test.

Other: Cold pressor test

Interventions

TruBeet inorganic beetroot juice DIETARY_SUPPLEMENT

400 mg nitrate-rich beetroot powder, mixed with 300 mL water.

Nitrate, caffeine, and cold pressor test (CPT); Nitrate, placebo caffeine, and CPT

Caffeine DIETARY_SUPPLEMENT

6 mg/kg caffeine powder in capsule form.

Nitrate, caffeine, and cold pressor test (CPT); Placebo nitrate, caffeine, and CPT

Cold pressor test OTHER

3 min cold pressor test using the left foot in cold water (0-2 degree).

Nitrate, caffeine, and cold pressor test (CPT); Nitrate, placebo caffeine, and CPT; Placebo nitrate, caffeine, and CPT; Placebo nitrate, placebo caffeine, and CPT

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Blood pressure \< 130 mmHg systolic and \< 85 mmHg diastolic. BMI between 18.5 and 29.9 kg/m2. Females must be naturally menstruating (regular length cycle and menses) or using a form of combined hormonal contraception (for at least 6 months).

You may not qualify if:

• 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.

Sponsors & Collaborators

• Loughborough University: lead
• Biogen Extracts Pvt Ltd: collaborator

Study Sites (1)

Loughborough University

Loughborough, LE11 3TU, United Kingdom

Location

MeSH Terms

Interventions

Caffeine

Intervention Hierarchy (Ancestors)

Xanthines; Alkaloids; Heterocyclic Compounds; Purinones; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Officials

• Stephen Bailey

  Loughborough University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Double-blinded using supplement placebos.
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: 24 participants will complete 4 experimental conditions in a randomized order.

Study Record Dates

• First Submitted: September 12, 2024
• First Posted: September 19, 2024
• Study Start: December 5, 2023
• Primary Completion: November 1, 2024
• Study Completion: April 1, 2025
• Last Updated: September 12, 2025

Record last verified: 2024-08

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)