Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolismeFeb 15, 2018

No effects of caffeine or beetroot juice on moderate or intense running performance

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Apr 6, 2026

Abstract

No significant differences were found in performance or physiological responses between caffeine, beetroot juice, or their combination during running.

Seven males and two females participated in the study, with average maximal oxygen uptake values of 59.0 mL·kg·min and 53.1 mL·kg·min, respectively.
Participants completed two submaximal running bouts and a maximal 1-km time trial in a controlled laboratory setting.
Supplementation included concentrated beetroot juice with or without nitrate and caffeine or a placebo before each test session.
No significant differences were observed in oxygen uptake, running economy, heart rate, or perceived exertion during submaximal intensities.
Maximal time trial performance showed no significant differences in maximum heart rate, peak blood lactate concentration, or perceived exertion across all interventions.

Simplified

Dietary supplements such as caffeine and beetroot juice are used by athletes in an attempt to optimize performance and therefore gain an advantage in competition. The aim of this study was to investigate the individual and combined effects of caffeine and beetroot-juice supplementation during submaximal and maximal treadmill running. Seven males (maximal oxygen uptake: 59.0 ± 2.9 mL·kg·min) and 2 females (maximal oxygen uptake: 53.1 ± 11.4 mL·kg·min) performed a preliminary trial followed by 4 experimental test sessions. Each test session consisted of two 5-min submaximal running bouts (at ∼70% and 80% of maximal oxygen uptake) and a maximal 1-km time trial (TT) in a laboratory. Participants ingested 70 mL of concentrated beetroot juice containing either 7.3 mmol of nitrate (BR) or no nitrate (P) 2.5 h prior to each test session, then either caffeine (C) at 4.8 ± 0.4 (4.3-5.6) mg/kg of body mass or a caffeine placebo (P) 45 min before each test session. The 4 test sessions (BR-C, BR-P, P-C, and P-P) were presented in a counterbalanced and double-blind manner. No significant differences were identified between the 4 interventions regarding relative oxygen uptake, running economy, respiratory exchange ratio, heart rate (HR), or rating of perceived exertion (RPE) at the 2 submaximal intensities (P > 0.05). Moreover, there were no significant differences in performance, maximum HR, peak blood lactate concentration, or RPE during the maximal TT when comparing the interventions (P > 0.05). In conclusion, no beneficial effects of supplementing with typical doses of caffeine, beetroot juice, or a combination of the two were observed for physiological, perceptual, or performance responses during submaximal or maximal treadmill running exercise. -1 -1 -1 -1BR C C BR BR C

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No effects of caffeine or beetroot juice on moderate or intense running performance

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