Impact of Dietary Nitrate Supplementation on VO2max During Ramadan Fasting in Healthy Adults

April 27, 2026 updated by: Philip Millar, University of Guelph

The goal of this clinical trial is to determine if beetroot juice supplementation changes exercise performance following one week of Ramadan fasting in young, healthy adults. The main question it aims to answer is:

Does daily beetroot juice supplementation change VO2 max in fasting individuals during the first week of Ramadan?

Participants will:

Visit the lab before the start of Ramadan and after one week of fasting If assigned to intervention group, consume daily shots of beetroot juice (70ml) during the first week of Ramadan fasting Perform maximal exercise testing on a cycle ergometer

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Recent literature demonstrates data showing a decrease in VO2max during the first week of Ramadan fasting. This is a practice observed by millions around the world every year, where individuals abstain from food and water from sunrise to sunset, dictated by the lunar calendar. Dietary nitrate consumption has been shown to increase VO2max and exercise performance. Therefore, the primary purpose of this study is to investigate whether dietary nitrate, in the form of beetroot juice, can help mitigate the decrease in VO2 max during the first week of Ramadan fasting.

24 young healthy adults will be recruited to undergo these two visits. The first visit will assess maximal oxygen uptake to determine aerobic fitness and metabolic exercise intensity zones under non-fasting conditions. The second visit will be completed after one week of Ramadan fasting. If assigned to the intervention group, participants will consume one shot (70ml) of Blonyx - Beet It Sport Nitrate 400 beetroot juice every day. Each shot contains 400mg of nitrates. Urine Specific Gravity will be measured after each visit to assess hydration status. The intervention group will also undergo Single Blood Draws after each visit to assess nitrate concentrations before and after a week of consumption.

Study Type

Interventional

Enrollment (Actual)

21

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
      • Guelph, Canada
        • University of Guelph

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Free of known cardiovascular or metabolic diseases or sleep disorders
  • No history of smoking (within the past 3 months)
  • Able to engage in physical activity assessed through the physical activity readiness questionnaire (PAR-Q+)
  • No prescription of chronic medications other than oral contraceptives
  • Able to abide by fasting protocols for all visits
  • Individuals who are not allergic to ultrasound gel or beetroot juice
  • Individuals who are not pregnant

Exclusion Criteria:

  • Individuals diagnosed with cardiovascular or metabolic disease or sleep disorders
  • Has a history of smoking (within the past 3 months)
  • Not ready to engage in physical activity as assessed by the PAR-Q+
  • Individuals prescribed chronic medications other than oral contraceptives
  • Unable to abide by fasting protocols for any testing visit
  • Allergic to ultrasound gel or beetroot juice
  • Pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: No Intervention
Normal Fasting, no intervention. During this arm, participants will be asked to complete an exercise test before and after 1 week of Ramadan fasting.
Experimental: Nitrate Supplementation
Participants will be asked to consume daily nitrate supplementation (70ml) in the form of beetroot juice for 7 days. Participants will then complete a maximal exercise test as they fast.
Dietary supplement: Beetroot Juice (Beet-It Stamina Shot) & Supervised Exercise Training
7 doses, taken daily, 70 ml shots, consumed in the morning before the start of fasting

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
VO2 max
Time Frame: One--week differences between before and after 1 week of fasting, nitrate supplementation if in intervention group
Maximal Oxygen Uptakes will be assessed to analyze aerobic capacity and fitness under fasting conditions.
One--week differences between before and after 1 week of fasting, nitrate supplementation if in intervention group

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Nitrate Concentration levels
Time Frame: Comparison between blood before and after nitrate supplementation: one week
Single blood draws will be taken after each visit for the nitrate supplementation group
Comparison between blood before and after nitrate supplementation: one week

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Guelph

Investigators

  • Principal Investigator: Phillip Millar, PhD, University of Guelph

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 6, 2025

Primary Completion (Actual)

March 31, 2025

Study Completion (Actual)

March 31, 2025

Study Registration Dates

First Submitted

January 6, 2025

First Submitted That Met QC Criteria

January 6, 2025

First Posted (Actual)

January 9, 2025

Study Record Updates

Last Update Posted (Actual)

May 1, 2026

Last Update Submitted That Met QC Criteria

April 27, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 25-01-006

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

IPD used in the results publication

IPD Sharing Time Frame

Beginning after publication with no end date

IPD Sharing Access Criteria

Phillip Millar, University of Guelph

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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