Effect of beetroot juice supplementation on 10-km performance in recreational runners. - GreenMedInfo Summary
Effect of beetroot juice supplementation on 10-km performance in recreational runners.
Appl Physiol Nutr Metab. 2018 Jul 9. Epub 2018 Jul 9. PMID: 29986146
Talitha Fernandes de Castro
The purpose of this study was to investigate the effects of chronic beetroot juice (BRJ) supplementation on 10-km running performance in recreational runners. In a double-blind, placebo-controlled, crossover-designed study, fourteen male recreational runners (age: 27.8± 3.4 y) performed three 10-km running tests at baseline, under the conditions of BRJ supplementation and placebo (PLA). Supplementation was administered for three days, and on the day of the assessments, the ingestion occurred two hours before each test and consisted of a dose of 420 mL of BRJ innatura (8.4 mmol NO3-/day) or PLA with depleted NO3- (0.01 mmol NO3-/day). The mean velocity (MV) was calculated and the following variables were determined: maximum heart rate (HRmax), maximal rating of perceived exertion (RPEmax), and determined at pre and post test glucose concentrations (Glycpre, Glycpost), and lactate peak. There was no main effect between conditions regarding to 10-km running time performance (BRJ: 50.1 ± 5.3; PLA: 51.0 ± 5.1 min, p = 0.391) and total MV (BRJ: 12.1 ± 1.3; PLA: 11.9 ± 1.2 km·h-1, p = 0.321), as well as in the other analyzed variables. The time to complete the first half of the test (5 km) was statistically lower in the BRJ compared to that in the PLA (P = 0.027). In conclusion, chronic supplementation with BRJ increasing MV in the first half of the test and improves the final test time of ten of the fourteen runners, although we did not find astatistically significant difference in the performance of 10-km.