The Most Overlooked Legal Performance-Enhancing Intervention in Endurance Sport Costs Less Than £2 Per Serving and Has Been in Your Kitchen All Along.

In 2009 and 2010, Andrew Jones and colleagues at the University of Exeter published a series of studies that changed how exercise scientists think about a vegetable. Dietary nitrate from beetroot reduced the oxygen cost of submaximal exercise by 3–5%. That is not a minor effect. At endurance-sport intensities, a 3–5% reduction in oxygen cost translates directly to improved performance at any fixed effort — and the mechanism is more precisely understood than most ergogenic aids that cost considerably more.

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The Nitrate-Nitrite-NO Pathway

The mechanism begins in the mouth, not the stomach:

1. Dietary inorganic nitrate (NO₃⁻) is absorbed in the small intestine and concentrated in saliva — salivary nitrate concentrations can reach 10× plasma levels 2. Anaerobic bacteria in the crypts of the tongue reduce nitrate to nitrite (NO₂⁻) — this step requires oral bacteria; it does not happen chemically in an acidic stomach environment 3. Swallowed nitrite reaches the acidic gastric environment and is partially converted to nitric oxide (NO) — a potent vasodilator and metabolic regulator 4. In hypoxic muscle tissue (exercising at high intensity), nitrite is further reduced to NO by deoxymyoglobin and other reductases

The resulting systemic NO elevation produces:

• Peripheral vasodilation — increased skeletal muscle blood flow and oxygen delivery
• Mitochondrial efficiency — reduced oxygen requirement per ATP produced (NO inhibits cytochrome c oxidase at Complex IV, reducing the O₂ cost of oxidative phosphorylation)
• Muscle contractile efficiency — particularly in Type II fast-twitch fibres, which have lower baseline nitrate reductase activity and show a proportionally larger response to exogenous nitrate

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The Evidence: Key Studies

Jones et al. 2010 (*Journal of Applied Physiology*): Eight competitive cyclists completed a 4.2 km time trial and a 16.1 km time trial after 6 days of beetroot juice (0.5L/day, ~5–6 mmol nitrate) or placebo. Results:

• 4.2 km TT: 2.8% faster with beetroot
• 16.1 km TT: 2.7% faster
• Oxygen consumption during submaximal cycling: 3% lower

Lansley et al. 2011 (*Medicine & Science in Sports & Exercise*): Single acute dose (0.5L beetroot juice, ~8 mmol nitrate) consumed 2.5 hours before a 4 km and 16.1 km TT in trained cyclists:

• 4 km TT: 2.7% faster
• 16.1 km TT: 1.5% faster
• Power output at a fixed VO₂: significantly higher with nitrate

Bailey et al. 2009 (*Journal of Applied Physiology*): Walking and moderate cycling with beetroot supplementation:

• Time to exhaustion at 80% VO₂max: 16% longer with nitrate

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The Mouthwash Paradox: Eliminating the Effect

This finding is critical for any athlete using antibacterial oral hygiene products pre-competition:

A 2011 study by Govoni et al. confirmed that using antibacterial mouthwash before or after nitrate ingestion completely eliminates plasma nitrite elevation — because the oral bacteria responsible for nitrate-to-nitrite conversion are killed.

Athletes who use Corsodyl (chlorhexidine) mouthwash or similar antibacterial rinses routinely: the entire performance benefit of dietary nitrate is negated. The nitrate passes through without reduction, and no NO is generated.

Practical rule: Avoid antibacterial mouthwash from 12 hours before nitrate supplementation through 2 hours post-ingestion. Standard fluoride toothpaste does not affect oral nitrate bacteria.

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Dosing and Timing Protocol

Dose: 5–8 mmol inorganic nitrate — equivalent to:

• ~500ml concentrated beetroot juice (most commercial brands)
• 2 × beetroot juice shots (70ml concentrated)
• ~200–300g raw beetroot (less reliable — concentration varies by soil and variety)

Timing: Peak plasma nitrite occurs 2–3 hours post-ingestion. Consume 2–3 hours before exercise for maximum performance benefit.

Duration: Chronic supplementation (5–6 days) produces slightly larger effects than acute single-dose, due to plasma nitrite accumulation. Acute single-dose is sufficient but suboptimal.

Trained athlete response: Effect magnitude is smaller in highly trained athletes (VO₂max >65 mL/kg/min) than in recreational athletes — likely due to higher baseline NO production through the NOS pathway. Not absent, but attenuated.

For runners and cyclists tracking performance metrics across training blocks where nitrate supplementation may be altering pace economy — distinguishing genuine fitness gains from supplementation effects on running pace data — the pace calculator at winsport.uk/tools/performance/running-pace-calculator calculates target paces across distances and training intensities, providing the baseline for evaluating whether pace improvements reflect true fitness adaptation.

Have you used dietary nitrate supplementation in your pre-competition protocol — and if so, have you tracked whether you're avoiding the mouthwash variable that eliminates the benefit?