Beetroot Supplementation and High Intensity Exercise

Study Overview
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Brief Summary
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Ingested beetroot contains inorganic nitrate which is later converted to nitric oxide (NO) in the bloodstream. NO is an important signaling molecule with several physiological functions in the body including acting as a vasodilator, expanding arteries and improving blood flow. Beetroot juice contain inorganic nitrate and consumption of beetroot has been shown to improve skeletal muscle contractility and metabolism enhancing high-intensity exercise performance. Isotonic sports drinks contain carbohydrates and sodium, which also improve exercise performance by providing exogenous glucose for energy to the working muscle and central nervous system and enabling faster absorption of fluid into the bloodstream. The ingestion of exogenous nitrate and isotonic-carbohydrate drink are recognized strategies for promoting exercise performance but whether they can be effectively combined has not been shown. This study will compare the salivary nitrite response, muscle oxygenation and time-trial performance after ingestion of two isotonic drinks with high in nitrate or with no nitrate.

Detailed Description
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Ingested beetroot contains inorganic nitrate (NO3-) which is later converted to nitric oxide (NO) in the bloodstream. NO is an important signaling molecule with several physiological functions in the body including acting as a vasodilator, expanding arteries and improving blood flow. These functions mean that beetroot juice has become of strong interest in the field of exercise and is a recommended supplement for athletes to improve performance in recent consensus statements by the International Olympic Committee on dietary supplements. Importantly, the consumption of beetroot has been shown to improve skeletal muscle contractility and metabolism, hence, enhancing high-intensity exercise performance . Isotonic sports drinks contain carbohydrates and sodium, which also improve exercise performance by providing exogenous glucose for energy to the working muscle and central nervous system and enabling faster absorption of fluid into the bloodstream. The ingestion of exogenous nitrate and isotonic-carbohydrate drink are recognized strategies for promoting exercise performance but whether they can be effectively combined has not been shown. This study will compare the salivary nitrite response, muscle oxygenation and time-trial performance after ingestion of two drinks either high in nitrate or with no nitrate. Participants will ingest the two drinks in a randomised, crossover double-blind trial. One hour after drink ingestion they will undertake high intensity intermittent exercise for 30 minutes followed by a 10 km time trial on a cycle ergometer. Time trial will be compared between trials as the main outcome. It is hypothesised that the drink high in nitrate will lead to faster time trial completion.

Official Title
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The Effect of Isotonic Beetroot Supplementation on High-intensity Time-trial Performance

Conditions
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Exercise Performance

Intervention / Treatment
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* Dietary Supplement: High nitrate isotonic drink
* Dietary Supplement: No nitrate isotonic drink


Participation Criteria
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Eligibility Criteria
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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 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 ethnicity by self identification Exclusion Criteria: Any allergies to beetroot or isotonic drink. Asthma. Any report of personal health issues that may compromise the individual's ability to undertake exercise safely. Any recent Covid vaccination (within last 2 weeks).

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High nitrate<br>High nitrate isotonic drink | Dietary Supplement: High nitrate isotonic drink<br>* High nitrate (12.9 mmol) drink with carbohydrate and minerals<br>|
| Active Comparator: No nitrate<br>No nitrate isotonic drink | Dietary Supplement: No nitrate isotonic drink<br>* Carbohydrate and mineral isotonic drink<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 10 km cycling time trial (endurance) performance | Time trial | 1 hour after drink ingestion the time taken to complete 10 km on a stationary cycle ergometer will be assessed. Time to complete this is the primary outcome measure . | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Salivary nitrate | Salivary nitrate concentration determined from strips | Four samples over 2 hours | 
| Near infra-red spectroscopy (NIRS) | Tissue saturation index | During cycling  1 hour |