Effectiveness of beetroot juice on aerobic and anaerobic exercise performance: systematic review and meta-analysis.

TL;DR

Beetroot juice supplementation produced small but consistent improvements across three measures of exercise performance: high-intensity sprint performance, mean power output, and maximal oxygen uptake . Effects were modest in magnitude but statistically significant across all outcomes.

What the Study Found

Researchers conducted a systematic review and meta-analysis of 33 studies examining how beetroot juice affects exercise performance. The supplement's ergogenic potential stems from its natural nitrate content, which the body converts to nitric oxide, a signaling molecule that influences blood flow and metabolic efficiency. This update synthesizes evidence that had previously been fragmented across aerobic and anaerobic performance domains.

The analysis found statistically significant improvements across all three primary outcomes. High-intensity interval sprint (HIS) performance improved with a standardized mean difference (SMD) of 0.38, meaning the average treatment group performed at roughly the 65th percentile compared to control groups. Mean power output showed a similar effect size of 0.43 SMD. Maximal oxygen uptake (VO2max), the gold standard aerobic fitness measure, improved by 0.30 SMD. All three findings achieved statistical significance with p values less than 0.001, and heterogeneity across studies was low to negligible, suggesting consistency in the direction and magnitude of effects.

The consistency of effects is noteworthy. Heterogeneity quantifies how much variation exists between studies beyond what chance would predict. Low heterogeneity across outcomes (ranging from 0.0% to 11.0%) indicates that despite methodological differences across the 33 studies, the core finding held relatively steady. This suggests the effect is robust rather than driven by outlier studies or specific experimental designs.

The authors identified several potential effect modifiers that warrant investigation in future research: athlete status (trained versus untrained), sport type, supplementation strategy (dosing protocols and timing), juice brand, and intake timing relative to exercise. Notably, subgroup analyses did not show statistically significant differences between these categories. The authors appropriately frame this as hypothesis-generating rather than definitive, meaning these patterns merit testing in designed comparisons but cannot be confirmed from the current data.

What This Means for You

The evidence supports beetroot juice as a low-risk ergogenic aid with measurable effects on exercise performance. For endurance athletes targeting VO2max improvements or competitive athletes focused on anaerobic power, the supplement shows consistent small-to-moderate benefit.

The practical significance depends on your context. A 0.38 SMD improvement in sprint performance translates roughly to 1-3% performance gains in real-world settings, which can matter in competitive contexts but may be imperceptible in casual training. For recreational exercisers, the performance gain is unlikely to be your primary consideration; safety and cost-effectiveness become more relevant.

Administration strategy appears flexible but remains to be optimized. The meta-analysis suggests timing, dosing, and brand may influence outcomes, but current evidence does not point to a single clearly superior approach. Most studied protocols used concentrated beetroot juice in the hours preceding exercise, making this a reasonable starting point if you choose to trial the supplement.

The low heterogeneity and consistent positive direction across studies is encouraging for reliability, but recognize that the absolute effect sizes are modest. This is distinct from claiming the supplement is not worth using; rather, it means benefits are incremental rather than transformative.

Study Details

Sources

Systematic review and meta-analysis. Frontiers in Nutrition. PubMed ID: 42445795