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Dietary nitrate supplementation enhances high-intensity running performance in moderate normobaric hypoxia, independent of aerobic fitness

Lookup NU author(s): Dr Oliver Shannon, Dr Jose Lara-Gallegos, Dr Mario Siervo

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


Abstract

Nitrate-rich beetroot juice (BRJ) increases plasma nitrite concentrations, lowers the oxygen cost (V O-2) of steady-state exercise and improves exercise performance in sedentary and moderately-trained, but rarely in well-trained individuals exercising at sea-level. BRJ supplementation may be more effective in a hypoxic environment, where the reduction of nitrite into nitric oxide (NO) is potentiated, such that well trained and less well-trained individuals may derive a similar ergogenic effect. We conducted a randomised, counterbalanced, double-blind placebo controlled trial to determine the effects of BRJ on treadmill running performance in moderate normobaric hypoxia (equivalent to 2500 m altitude) in participants with a range of aerobic fitness levels. Twelve healthy males (V O-2max ranging from 47.1 to 76.8 ml kg(-1) min(-1)) ingested 138 ml concentrated BRJ (similar to 15.2 mmol nitrate) or a nitrate-deplete placebo (PLA) (similar to 0.2 mmol nitrate). Three hours later, participants completed steady-state moderate intensity running, and a 1500 m time-trial (TT) in a normobaric hypoxic chamber (F1O2 similar to 15%). Plasma nitrite concentration was significantly greater following BRJ versus PLA 1 h post supplementation, and remained higher in BRJ throughout the testing session (p < 0.01). Average V O-2 was significantly lower (BRJ: 18.4 +/- 2.0, PLA: 20.4 +/- 12.6 ml kg(-1)min(-1) ; p = 0.002), whilst arterial oxygen saturation (SpO2) was significantly greater (BRJ: 88.4 +/- 2.7, PLA: 86.5 +/- 3.3%; p < 0.001) following BRJ. BRJ improved TT performance in all 12 participants by an average of 3.2% (BRJ: 331.1 +/- 45.3 vs. PL: 341.9 +/- 46.1 s; p < 0.001). There was no apparent relationship between aerobic fitness and the improvement in performance following BRJ (r(2) = 0.05, p > 0.05). These findings suggests that a high nitrate dose in the form of a BRJ supplement may improve running performance in individuals with a range of aerobic fitness levels conducting moderate and high-intensity exercise in a normobaric hypoxic environment. (C) 2016 Elsevier Inc. All rights reserved.


Publication metadata

Author(s): Shannon OM, Duckworth L, Barlow MJ, Woods D, Lara J, Siervo M, O'Hara JP

Publication type: Article

Publication status: Published

Journal: Nitric Oxide: Biology and Chemistry

Year: 2016

Volume: 59

Pages: 63-70

Print publication date: 30/09/2016

Online publication date: 20/08/2016

Acceptance date: 11/08/2016

Date deposited: 07/02/2018

ISSN (print): 1089-8603

ISSN (electronic): 1089-8611

Publisher: Academic Press

URL: https://doi.org/10.1016/j.niox.2016.08.001

DOI: 10.1016/j.niox.2016.08.001


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