Effect of beetroot juice supplementation on mood, perceived exertion and performance during a 30 s Wingate test

Purpose: Dietary supplementation with inorganic nitrate (NO3-) can enhance high- intensity exercise performance by improving skeletal muscle contractility and metabolism, but the extent to which this might be linked to altered psychophysiological processes is presently unclear. The purpose of this study was to assess the effects of NO3--rich beetroot juice (BJ) supplementation on profile of mood states (POMS), ratings of perceived exertion (RPE) and performance in a 30 s Wingate cycle test. Methods: In a double blind, randomized, crossover study, 15 subjects completed two laboratory sessions after ingesting NO3--rich or NO3--depleted (placebo) BJ. Participants initially completed the POMS questionnaire. Subsequently, participants completed a warm-up followed by a 30 s all-out Wingate cycling test. After the Wingate test, participants immediately indicated the RPE of their leg muscles (RPEmuscular), cardiovascular system (RPEcardio) and general RPE (RPEgeneral). Results: Compared to the placebo condition, supplementation with BJ increased peak power output (Wpeak) (+4.4%, 11.5 ± 0.7 vs. 11.1 ± 1.0 W·kg-1, p = 0.039) and lowered the time taken to reach Wpeak (7.3 ± 0.9 vs. 8.7 ± 1.5 s, p = 0.002) during the Wingate test. The POMS score linked to tension was increased prior to the Wingate test (4.8 ± 3.0 vs. 3.4 ± 2.4, p = 0.040), and RPE muscular was lowered immediately following the Wingate test (17.7 ± 1.6 vs. 18.3 ± 1.0, p = 0.031), after BJ compared to placebo ingestion. Conclusions: Acute BJ supplementation improved pre-exercise tension, and 30 s Wingate test performance, and lowered post-exercise RPE muscular.