Beetroot Nitrates: Blood Pressure and Exercise Performance

The story of beetroot juice as an ergogenic aid began with a 2007 paper by Andy Jones and colleagues at the University of Exeter showing that 500 mL of beetroot juice reduced the oxygen cost of cycling by about 5 percent and extended time to exhaustion by about 16 percent. The active ingredient is not the beet itself but dietary nitrate, which the body converts to nitrite and then to nitric oxide, a signaling molecule that dilates blood vessels and improves mitochondrial efficiency. Since 2007, dozens of trials have tested beetroot juice for endurance performance, blood pressure, and cardiovascular health. The evidence is real but specific, and the dose and timing matter enormously.

How dietary nitrate works in the body

The active pathway starts with nitrate (NO3-) from food. About 25 percent of ingested nitrate is taken up by the salivary glands and concentrated in saliva. Oral bacteria on the tongue then reduce nitrate to nitrite (NO2-). The nitrite is swallowed, absorbed in the stomach and intestines, and enters circulation. Under low-oxygen conditions, nitrite is further reduced to nitric oxide (NO), a potent vasodilator and signaling molecule.

This pathway is biologically distinct from the classical nitric oxide pathway that operates through the enzyme nitric oxide synthase (NOS). The NOS pathway uses the amino acid L-arginine as a substrate and requires oxygen. The nitrate-nitrite-nitric oxide pathway works without NOS and without oxygen, which is why it may be particularly important during exercise when local tissue oxygen drops.

The salivary bacteria step is essential. This is the reason antibacterial mouthwash blocks the entire pathway: chlorhexidine and other antiseptic mouthwashes kill the bacteria on the tongue that convert nitrate to nitrite. Multiple trials have shown that using mouthwash after consuming nitrate wipes out the blood pressure and exercise effects.

Sources of dietary nitrate

Vegetables are by far the main source of dietary nitrate. Leafy greens and root vegetables dominate:

• Rhubarb: 281 mg per 100 g
• Arugula (rocket): 480 mg per 100 g
• Celery: 250 mg per 100 g
• Beetroot: 250 mg per 100 g (varies widely by variety and growing conditions)
• Spinach: 182 mg per 100 g
• Lettuce: 200 mg per 100 g
• Radish: 240 mg per 100 g
• Cress: 230 mg per 100 g

Values vary widely depending on soil, growing conditions, variety, season, and storage. A glass of beetroot juice typically delivers 400 to 800 mg of nitrate, depending on the brand and concentration. Concentrated beetroot juice shots (about 70 mL) deliver a similar nitrate load in less volume.

The so-called DASH diet, which is associated with lower blood pressure, may work partly through its high nitrate content. The DASH eating pattern emphasizes leafy greens, vegetables, and low-fat dairy, which together deliver much more nitrate than the typical American diet.

Beetroot and blood pressure

The blood pressure evidence is the strongest and most consistent for dietary nitrate. A 2013 meta-analysis by Siervo and colleagues in the Journal of Nutrition pooled 16 trials and found that beetroot juice supplementation reduced systolic blood pressure by an average of 4.4 mmHg and diastolic by 1.1 mmHg. The effect was dose-dependent, with larger effects at higher nitrate doses.

A 2018 meta-analysis by Khanna and colleagues in Advances in Nutrition pooled 26 trials and found similar effects: a 3.7 mmHg reduction in systolic and 1.7 mmHg reduction in diastolic blood pressure with nitrate-rich vegetable juices.

The effect size is clinically meaningful. A 4 mmHg reduction in systolic blood pressure at the population level is estimated to reduce stroke mortality by about 14 percent and coronary heart disease mortality by about 9 percent. The American Heart Association's hypertension guideline lists nitrate-rich vegetable consumption as one of several lifestyle measures that can lower blood pressure, though it does not recommend beetroot specifically.

The blood pressure effect appears within 2 to 3 hours of consuming beetroot juice and lasts about 24 hours. Daily dosing maintains the effect. The effect is larger in people with higher baseline blood pressure and smaller in people with normal blood pressure.

Beetroot and exercise performance

The exercise story is more nuanced than the blood pressure story. The original 2007 study by Lansley and colleagues in the Journal of Applied Physiology tested nine club-level cyclists in a double-blind, placebo-controlled crossover design. The beetroot juice group reduced oxygen cost of cycling at a fixed workload by about 5 percent and extended time to exhaustion by about 16 percent. The effect was striking and unexpected.

Subsequent trials have refined the picture. A 2018 systematic review by Jones and colleagues in the European Journal of Sport Science, often cited as the Jones 2018 review, pooled 47 trials of dietary nitrate for exercise performance. The pooled effect showed a modest but significant improvement in time-to-exhaustity tests (about 25 percent on average, which sounds large but reflects the nature of these tests) and a smaller improvement in time-trial performance (about 1 to 3 percent).

The key insight from the literature: beetroot helps most for events lasting 4 to 30 minutes at high intensity, where oxygen delivery and mitochondrial efficiency are limiting. The effect is smaller or absent for very short events (under 60 seconds, which are anaerobic) and very long events (over 60 minutes, where other factors dominate). It also helps most in recreational and moderately trained athletes. In elite athletes, the effect is much smaller, possibly because they already have maximized nitric oxide production.

Specific populations where beetroot has shown the largest benefit:

• Recreational runners and cyclists in events lasting 5 to 30 minutes (1 to 3 percent improvement in time-trial performance)
• Older adults doing aerobic exercise (improved muscle efficiency and oxygen cost)
• People with COPD or heart failure doing exercise rehabilitation (improved exercise tolerance)
• Altitude exposure (reduced oxygen cost at high altitude)

Populations where the effect is small or absent:

• Elite endurance athletes (already maximized)
• Sprint events under 60 seconds (anaerobic)
• Resistance training (the mechanism is oxygen efficiency, not strength)
• Well-trained masters athletes in events over 60 minutes

Dosing and timing

The effective dose in most trials is 6 to 13 mmol (about 400 to 800 mg) of nitrate taken 2 to 3 hours before exercise. This is roughly:

• 500 mL of standard beetroot juice
• 70 mL of concentrated beetroot juice shot
• 200 g of cooked beetroot
• 100 g of raw spinach or arugula

The peak effect on blood nitrite levels occurs about 2 to 3 hours after consumption. The effect on exercise performance can last up to 24 hours, but the peak window is roughly 2 to 5 hours post-ingestion.

A loading protocol over 3 to 15 days may be more effective than a single pre-event dose. Several trials have shown that daily beetroot juice for 3 to 7 days, with a final dose 2 to 3 hours before exercise, produces larger and more consistent effects than a single acute dose. This is partly because the body needs time to ramp up the nitrate-reduction machinery in oral bacteria and partly because tissue nitrite stores accumulate.

Avoid antibacterial mouthwash for at least 24 hours before and after consuming beetroot juice. This is the single most important practical point. Chlorhexidine mouthwash can eliminate the effect entirely by killing the bacteria that convert nitrate to nitrite.

The mouthwash interaction: a practical warning

The oral microbiome is essential to the nitrate-nitrite-nitric oxide pathway. Multiple trials have confirmed that disrupting oral bacteria with antiseptic mouthwash prevents the conversion of nitrate to nitrite and eliminates both the blood pressure and exercise effects.

A 2019 study by Bondonno and colleagues in Free Radical Biology and Medicine tested the impact of chlorhexidine mouthwash on the blood pressure response to beetroot juice in 19 adults. Without mouthwash, beetroot juice reduced systolic blood pressure by about 5 mmHg. With chlorhexidine mouthwash used twice daily, the blood pressure reduction was eliminated, and salivary nitrite levels did not rise.

The implication for athletes and people using beetroot for blood pressure: avoid antiseptic mouthwash (Listerine, chlorhexidine, etc.) for at least 24 hours before and after consuming beetroot. Regular mechanical oral hygiene (tooth brushing, flossing) is fine. The bacteria involved live on the back of the tongue, where mouthwash hits them hardest.

Safety and side effects

Beetroot and dietary nitrate are generally safe. The main side effects are cosmetic and gastrointestinal:

• Pink urine (beeturia) and pink stools: harmless, occurs in about 10 to 15 percent of people, due to excretion of betalain pigments
• Gastrointestinal discomfort: beetroot juice can cause bloating, cramping, and diarrhea in some people, particularly at higher doses or when consumed immediately before exercise
• Staining: fresh beetroot stains everything it touches

There is a long-running concern that very high nitrate intake could form carcinogenic nitrosamines in the stomach, particularly when nitrate is consumed with protein-rich foods at high temperatures (think processed meats, which are preserved with nitrite). This concern was the basis for the WHO's classification of processed meat as a Group 1 carcinogen in 2015. However, vegetables contain vitamin C and polyphenols that inhibit nitrosamine formation. Multiple epidemiological studies have shown that vegetable-derived nitrate does not increase cancer risk, and may even reduce it. The carcinogenicity concern is specific to processed meats, not to nitrate-rich vegetables.

The European Food Safety Authority set an acceptable daily intake for nitrate of 3.7 mg per kg of body weight in 2017. A 70 kg adult would need to consume about 260 mg of nitrate per day to hit this limit. A single beetroot juice shot delivers about 400 to 800 mg, which technically exceeds the ADI. The EFSA noted that the benefits of vegetable nitrate likely outweigh the theoretical risk at typical vegetable intakes, but recommended against chronic very high intakes from supplements or concentrated juices without medical supervision.

Practical guidance

• For blood pressure: 500 mL of beetroot juice or one 70 mL concentrated shot per day, taken in the morning. Effects appear within 2 to 3 hours and persist for 24 hours with daily dosing. Stop using antiseptic mouthwash or use it at least 12 hours apart from beetroot.
• For endurance exercise: 6 to 13 mmol of nitrate (one 70 mL concentrated shot or 500 mL of standard juice) 2 to 3 hours before exercise. A loading protocol of 3 to 7 days may improve consistency.
• For older adults or people doing cardiac rehabilitation: daily beetroot juice or increased nitrate-rich vegetables (leafy greens, beets) may improve exercise tolerance.
• If you cannot tolerate beetroot juice, whole beets, arugula, spinach, and other nitrate-rich vegetables provide the same nitrate, just in larger volumes.
• Avoid antiseptic mouthwash (Listerine, chlorhexidine) for at least 24 hours around beetroot dosing, or it will not work.

Check your cardiovascular risk with the Blood Pressure Calculator or estimate your VO2 max with the VO2 Max Calculator.

The bottom line

Beetroot juice and other nitrate-rich vegetables have solid evidence for modest blood pressure reduction (about 4 mmHg systolic) and modest exercise performance improvement (1 to 3 percent in time-trial events of 5 to 30 minutes, mostly in recreational athletes). The effect depends on the dose, the timing, and the absence of antiseptic mouthwash, which kills the bacteria that make the pathway work. For general cardiovascular health, eating more nitrate-rich vegetables (beets, arugula, spinach, celery, lettuce) is a low-risk addition to a DASH-style diet. For athletic performance, a 70 mL concentrated beetroot juice shot 2 to 3 hours before exercise, ideally after 3 to 7 days of loading, is the best-supported protocol. Do not expect dramatic effects. The 1 to 3 percent improvement is real but modest, and mostly relevant to recreational athletes in specific event types, not to elite competitors or to people looking for a quick fix.