Effects of chronic beetroot juice supplementation on maximum oxygen uptake, velocity associated with maximum oxygen uptake, and peak velocity in recreational runners: a double-blinded, randomized and crossover study.

PURPOSE

This study investigated the effects of chronic 3-day beetroot juice (BRJ) supplementation on maximum oxygen uptake (VO), velocity associated with VO(vVO), and peak velocity (V) in recreational runners.

METHODS

Thirteen male recreational runners (age 28.2 ± 3.0 years, height 176.8 ± 0.1 cm, body mass 74.4 ± 9.5 kg) performed four tests on a treadmill in a randomized, double-blind, crossover design: two maximum incremental tests to determine VO and vVO and two tests to determine V. Trials were performed following 3 days of supplementation of NO-rich BRJ in natura (8.4 mmol NO day) or BRJ NO-depleted placebo (0.01 mmol NO day), with the last dose being ingested 2 h before each test. During the tests, maximum heart rate (HR), maximal rating of perceived exertion (RPE), pre- and post-test glucose concentrations (Gluc Gluc), and peak blood lactate concentration were determined.

RESULTS

VO was higher following BRJ vs PLA (46.6 ± 6.4 vs 45.1 ± 5.8 mL kg min; P = 0.022), as well as vVO (14.5 ± 0.8 vs 13.9 ± 1.0 km hP = 0.024) and V (15.5 ± 1.1 vs 15.2 ± 1.2 km hP = 0.038), with no differences in the other variables.

CONCLUSION

Consumption of NO-rich BRJ in natura (8.4 mmol NO day) once per day for 3 days improved VO, vVO and V in recreational runners without changing the other analyzed variables.