Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolismeMay 10, 2024

Effects of a single dose of dietary nitrate on oxygen use and muscle effort during intense forearm exercise in men

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Mar 29, 2026

Abstract

Supplementation with beetroot juice (BRJ) does not influence oxygen delivery or exercise performance during maximal effort handgrip exercise.

Healthy males participated in a randomized crossover trial assessing the effects of BRJ on forearm critical impulse performance.
Oxygen extraction was significantly better with placebo compared to BRJ.
A drink × time interaction indicated that oxygen consumption per unit of force was also better with placebo than BRJ during specific time intervals post-exercise.
BRJ did not significantly affect oxygen delivery, overall oxygen consumption, or levels of metabolites such as lactate and pH.
The oxygen cost of contraction was reduced with BRJ as contraction impulse declined during maximal effort exercise.

Simplified

Beetroot juice supplementation (BRJ) should increase nitric oxide bioavailability under conditions of muscle deoxygenation and acidosis that are a normal consequence of the maximal effort exercise test used to identify forearm critical impulse. We hypothesized BRJ would improve oxygen delivery:demand matching and forearm critical impulse performance. Healthy males (20.8 ± 2.4 years) participated in a randomized crossover trial between October 2017 and May 2018 (Queen's University, Kingston, ON). Participants completed 10 min of rhythmic maximal effort forearm handgrip exercise 2.5 h post placebo (PL) vs. BRJ (9 completed PL/BRJ vs. 4 completed BRJ/PL) within a 2 week period. Data are presented as mean ± SD. There was a main effect of drink (PL > BRJ) for oxygen extraction ( = 0.033, η= 0.351) and oxygen consumption/force ( = 0.017, η= 0.417). There was a drink × time interaction (PL > BRJ) for oxygen consumption/force ( = 0.035, η= 0.216) between 75 and 360 s (1.25-6 min) from exercise onset. BRJ did not influence oxygen delivery ( = 0.953, η= 0.000), oxygen consumption ( = 0.064, η= 0.278), metabolites ((lactate) ( = 0.196, η= 0.135), pH ( = 0.759, η= 0.008)) or power-duration performance parameters (critical impulse ( = 0.379, = 0.253), W' ( = 0.733, = 0.097)). BRJ during all-out handgrip exercise does not influence oxygen delivery or exercise performance. Oxygen cost of contraction with BRJ is reduced as contraction impulse is declining during maximal effort exercise resulting in less oxygen extraction. P P P P P P P P d P d p p p p p p p2 2 2 2 2 2 2

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Competing interests

The authors declare there are no competing interests.

PubMed

Effects of a single dose of dietary nitrate on oxygen use and muscle effort during intense forearm exercise in men

Abstract

Full Text

Funding

Competing interests

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