Effects of Isotonic Beetroot Supplementation on Sprint Interval Exercise Performance

The Effects of Isotonic Beetroot Supplementation on Sprint Interval Exercise Performance.

This study aims to examine the effects of dietary nitrate supplementation via beetroot juice on sprint interval cycling exercise performance. Twenty-four participants (male or female) will undertake a randomized, crossover trial where they consume either (i) an isotonic beetroot juice drink containing nitrate (12.9 mmol) for 5 days or (ii) an isotonic sports drink (no nitrate) for 5 days. On Day 5 of each trial, participants will come to the laboratory and 2 hours after consuming their allocated drink will complete a 6 bouts of sprint interval exercise. Power output during cycling will be measured as the primary outcome measure. Salivary and plasma measures of nitrate and nitrite will be taken over the course of the morning on Day 5. After a 5-day washout period participants will crossover and begin their second trial.

Study Overview

• Status: Completed
• Conditions: Exercise Performance
• Intervention / Treatment: Other: Dietary Supplement: High nitrate isotonic drink; Other: Dietary Supplement: No nitrate isotonic drink

Detailed Description

This study aims to examine the effects of dietary nitrate supplementation via beetroot juice on sprint interval cycling exercise performance. Twenty-four participants (male or female) will undertake a randomized, crossover trial where they consume either (i) an isotonic beetroot juice drink containing nitrate (12.9 mmol) for 5 days or (ii) an isotonic sports drink (no nitrate) for 5 days. Drinks will be equivalent in isotonicity and colored the same so that participants and investigators will be blinded to each trial. Randomization and drink allocation will be completed by a third person not associated with the study team. On Day 5 of each trial, participants will come to the laboratory and 2 hours after consuming their allocated drink will complete a 6 bouts of sprint interval exercise (10 second all-out maximal sprints interspersed with 50 seconds rest). Power output (peak and mean) during cycling sprints will be measured as the primary outcome measure. Salivary measures of nitrate/nitrite will be taken at three time points over the course of the morning on Day 5 - (i) pre-drink consumption; (ii) 2 hours post-drink consumption; and (iii) post-exercise. Plasma measures of nitrate and nitrite will be taken at two time points over the course of the morning on Day 5 - (i) pre-drink consumption; and (ii) 2 hours post-drink consumption. Near infra-red spectroscopy (NIRS) will be used to measure muscle (vastus lateralis) oxygenation during cycling bouts. A Stroop test to measure inhibition (executive function) will be taken pre- and post-exercise. Sensory perception of the drink will be measured immediately post-consumption on Day 5. After a 5-day washout period participants will crossover and begin their second trial.

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Singapore
  • Singapore, Singapore, 637616
    • Human Bioenergetics Laboratory, National Institute of Education, Nanyang Technological University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age: 21 - 40 years
• Healthy and injury-free (e.g., no cardiovascular disease, diabetes mellitus, orthopaedic impairment that interferes with moderate-to-vigorous exercise)
• Blood pressure < 130/90 mmHg
• Be physically active: Engaging in a minimum of 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity physical activity each week.
• Recreational cyclist (Minimum 1 hour cycling per week).
• Body mass index: 18.5-25 kg/m2
• Non-smoker
• Asian

Exclusion Criteria:

• Any allergies to beetroot or isotonic drink.
• Asthma
• Any diagnosed form of cardiometabolic disease (heart disease, stroke, peripheral vascular disease, diabetes, metabolic syndrome, high blood pressure).
• Any symptoms contraindicating exercise testing (e.g. chest pains).
• Any balance or dizziness problems.
• Any chronic medical conditions (whether medicated or not).
• Any bone joint problems.
• Any Physician diagnosed contraindications to exercise.
• Any other health problems that may be a cause for concern or contraindication to exercise.
• Any recent Covid vaccination (within last 2 weeks).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High nitrate; High nitrate isotonic drink	Other: Dietary Supplement: High nitrate isotonic drink; High nitrate (12.9 mmol) drink with carbohydrate and minerals
Active Comparator: No nitrate; No nitrate isotonic drink	Other: Dietary Supplement: No nitrate isotonic drink; Carbohydrate and mineral isotonic drink

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Power output during maximal sprint cycling	Peak and mean power output	2 hours after drink ingestion

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma nitrate and nitrite	Plasma nitrate and nitrite	Pre-drink and 2 hours post-drink
Salivary nitrate	Salivary nitrate/nitrite concentration	Pre-drink, 2 hours post-drink and immediately post-exercise (2.5 hours post-drink)
Muscle oxygenation	Near infra-red spectroscopy	During exercise (2-2.5 hours post drink)
Sensory evaluation (Acceptance and Preference Test Evaluation by Meilgaard et al 2007)	Drink taste and perception (7-point scale - 1 extremely dislike to 7 extremely like)	Immediately post-drink (1 minute post-drink)
Stroop test	Reaction time and correct answers	Immediately pre- (2 hours post-drink) and immediately post-exercise (2.5 hours post drink)

Collaborators and Investigators

• Sponsor: Nanyang Technological University

Study record dates

Study Major Dates

• Study Start (Actual): February 20, 2024
• Primary Completion (Actual): May 31, 2024
• Study Completion (Actual): May 31, 2024

Study Registration Dates

• First Submitted: February 20, 2024
• First Submitted That Met QC Criteria: March 31, 2024
• First Posted (Actual): April 5, 2024

Study Record Updates

• Last Update Posted (Actual): April 13, 2025
• Last Update Submitted That Met QC Criteria: April 10, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: IRB-2023-972

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All published data will be placed into the Data Repository of Nanyang Technological University National Institute of Education for public access upon publication.
• IPD Sharing Time Frame: Upon publication - permanent repository
• IPD Sharing Access Criteria: Public repository - exact web address available upon publication.
• IPD Sharing Supporting Information Type: ANALYTIC_CODE

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