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Beet out your competition with dietary nitrate!

Beets have shown promise for solo exercise, but what about for longer activity typical of team sports?

Study under review: Dietary nitrate improves sprint performance and cognitive function during prolonged intermittent exercise

Introduction

If you thought the benefits of consuming beetroot were limited to the lowered blood pressure effect you read about in the NERD last March, guess again! Beetroot juice is also one of the hottest (relatively) new supplements that may provide an ergogenic boost during exercise. Nitrates in beets can be converted to nitrites, which then serve as a precursor for the production of nitric oxide, a signaling molecule that plays an important role in a number of physiological processes that can impact exercise performance, including muscle contractility, mitochondrial efficiency, and the regulation of blood flow to working muscles. This has led to athletes of all levels consuming beetroot juice in an attempt to improve performance.

Recent research has shown improved running[1], swimming[2], and rowing[3] performance after beetroot juice consumption. Studies have frequently used short duration protocols, none of which mimic the longer durations typical of team sport play. To draw more relevant conclusions for athletes competing in sports like soccer, rugby, or field hockey, a study design that incorporates two 30-45 minute ‘halves’ is helpful.

Cognitive ability refers to a person’s ability to react, make decisions, learn, and communicate. During intense exercise these skills, particularly reaction time[4], deteriorate. Along with the traditionally sought-after benefits of an ergogenic aid, like improved strength, power, and endurance, improved reaction time is something that could be of benefit to athletes in nearly every sport. Because nitrate supplementation has been shown to improve blood flow to the brain (particularly to areas associated with executive function[5]) and enhance the blood flow response to visual stimuli[6], it is thought that nitrates could be beneficial during athletic competition.

As this had not been previously studied in a model of team sport performance, researchers attempted to study the effects of nitrate supplementation on cognitive performance during intermittent high-intensity exercise. Previous research[7] has shown no improvements in cognitive function during moderate intensity cycling exercise after a single dose of beetroot juice supplementation. However, exercise tolerance in that study was increased by 16%.

The purpose of this study was to examine the effects of one week of dietary nitrate supplementation on exercise performance and cognitive function during a repeated sprint test protocol designed to reflect work and recovery patterns that typically occur during team sport play.

Beetroot juice is rich in nitrates, and may be useful as an ergogenic aid. However, most studies to date have tested only its shorter-term performance, which may not be relevant to longer-duration activities like rugby or soccer. Nor has there been much research on the effects of beetroot juice on mitigating the impact of physical activity on cognition and reaction time. The goal of this study was to test the effects of beetroot juice on performance and cognition during longer-duration physical activity.

Who and what was studied?

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The big picture

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Other Articles in Issue #09 (July 2015)