Acute Beetroot Juice Supplementation Enhances Intermittent Running Performance but Does Not Reduce Oxygen Cost of Exercise among Recreational Adults

Nitrate (NO₃⁻) supplementation has been reported to enhance intermittent exercise performance; however, its impact on oxygen (O₂) cost during intermittent running exercise is unclear. The aim of this study was to assess if acute NO₃⁻ supplementation would elicit performance benefits in recreationally active individuals during the Yo–Yo intermittent recovery level 1 (Yo-Yo IR1) test, with its potential benefit on O₂ consumption (VO₂), in a double-blind, randomized, crossover study, 12 recreational males consumed NO₃⁻-rich (NIT; ~12.8 mmol), and NO₃⁻-depleted (PLA; 0.04 mmol) concentrated beetroot juice 3 h before completing the Yo-Yo IR1 test. VO₂ was measured at 160, 280 and 440 m (sub-maximal) and when the test was terminated (peak). Performance in the Yo–Yo IR1 was greater with NIT (990 ± 442.25 m) compared to PLA (870 ± 357.4 m, p = 0.007). The VO₂ was not significantly different at 160 m (1.92 ± 0.99 vs. 2.1 ± 0.88 L·min⁻¹), 280 m (2.62 ± 0.94 vs. 2.83 ± 0.94 L·min⁻¹), 440 m (3.26 ± 1.04 vs. 3.46 ± 0.98 L·min⁻¹) and peak (4.71 ± 1.01 vs. 4.92 ± 1.17 L·min⁻¹) between NIT and PLA trials (all p > 0.05). The present study has indicated that acute supplementation of NO₃⁻ enhanced intermittent running performance but had no effect on VO₂ during the Yo–Yo IR1 test in recreational young adults.