Studies Prove Consuming Nitrates Improves Performance

Larsen et al., 2007

The first study to show that inorganic nitrate supplementation may improve exercise efficiency was published in 2007 by Larsen et al.   In that study, nine well trained subjects consumed 0.1 mmol/kg body mass (BM) per day of sodium nitrate or a placebo for 3 days before completing a continuous incremental cycle ergometer test.  Nitrate supplementation significantly elevated resting plasma [nitrite] (by 82 %) and reduced resting systolic and diastolic blood pressure (by 8 and 6 mmHg).  The oxygen cost of exercise over the first four stages of the test was significantly reduced after nitrate supplementation compared with placebo, with a mean reduction in VO₂ of 5 %.

The findings of Larsen et al. are remarkable because a basic principal of human exercise physiology is that the oxygen cost of submaximal exercise at a given work rate is essentially fixed, irrespective of age, health, and fitness status, and insensitive to known physical, nutritional, or pharmacological interventions.  It is well established that endurance exercise performance is a function of VO_{2 max}, the fractional utilization of VO_{2 max}, and exercise efficiency.  Assuming that the other factors remain unchanged, an improvement in muscle efficiency would be expected to enable a greater work output for the same energy cost and translate into improved exercise performance.

Bailey et al., 2009

Recognizing the potential importance of the results of Larsen et al. to the enhancement of performance, Bailey et al. examined the influence of dietary nitrate supplementation on VO₂ dynamics during step exercise tests of moderate intensity and high intensity, with the latter tests continued to exhaustion as a measure of exercise tolerance.  An important difference from the study of Larsen et al. was that Bailey et al. used a natural nitrate-rich dietary source, beetroot juice, as the nitrate supplement.

Eight healthy men consumed 0.5 l/day of either beetroot juice (5.6 mmol nitrate) or blackcurrant cordial as a placebo for 6 consecutive days, with the exercise tests completed on the last 3 days.  On days 4–6 of the supplementation periods, plasma [nitrite] was significantly elevated following nitrate intake compared with placebo (95 %), and systolic blood pressure was significantly reduced (by an average of 8 mmHg).

During moderate-intensity exercise, steady-state VO₂ was reduced by 5 %.  During high-intensity exercise, there was a significant 23 % reduction in the amplitude of the VO₂ ‘slow component,’ which is considered to reflect a progressive loss of muscle efficiency as high-intensity exercise proceeds.  The peak VO₂ attained during high-intensity exercise was not different between treatments, but attainment of the peak VO₂ was delayed with nitrate such that the time to exhaustion was significantly increased by 16 %.  Consistent with the study of Larsen et al., nitrate did not alter blood [lactate], heart rate, ventilation, or respiratory exchange ratio for either moderate- or high-intensity exercise.  In a subsequent study using knee extensor exercise, Bailey et al. confirmed that, compared with placebo, beetroot juice consumption reduced submaximal VO₂ during low-intensity exercise, reduced the VO₂ ‘slow component’, and increased time to exhaustion by 25 % during high-intensity exercise.

What’s it all mean?

The results from the studies indicate that the effects of supplementation of nitrates on efficiency are clear, albeit perhaps less impressively, when normal dietary nitrate intake is not restricted.  There were significant increases in the peak power output and the power output at the gas exchange threshold compared with placebo, after 15 days of beetroot juice supplementation.  In addition to nitrate, beetroot juice also contains other compounds that may be independently bioactive or that may act synergistically with nitrate, including antioxidants (betaine and vitamins) and the polyphenols, resveratrol and quercetin.

Concentrated beetroot juice powders, like BeetBoost, are a convenient and easy to consume option for athletes looking to gain an edge or give their performance a boost.  Juicing raw beetroot juice is messy, time consuming, and requires consuming 6 beets to get the same benefits of one serving of BeetBoost.  If the flavor of beets aren’t your cup of tea, try blending BeetBoost into smoothies, or adding it into hummus. They’re also a surprisingly sweet addition to pancakes, muffins, or granola bars.