A Single Dose of Beetroot Juice Enhances Cycling Performance in Simulated Altitude

Muggeridge, David J.1,2; Howe, Christopher C. F.2; Spendiff, Owen2; Pedlar, Charles3; James, Philip E.4; Easton, Chris1,2

Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0b013e3182a1dc51
Applied Sciences
Abstract

Introduction: Increasing nitric oxide bioavailability via supplementation with nitrate-rich beetroot juice (BR) has been shown to attenuate the negative effect of hypoxia on peripheral oxygen saturation and exercise tolerance.

Purpose: We investigated the effects of a single dose of concentrated BR on the physiological responses to submaximal exercise and time trial (TT) performance in trained cyclists exposed to moderate simulated altitude (approximately 2500 m).

Methods: Nine competitive amateur male cyclists (age, 28 ± 8 yr; V˙O2peak at altitude, 51.9 ± 5.8 mL·kg−1·min−1) completed four exercise trials consisting of an initial graded test to exhaustion and three performance trials on a cycle ergometer. The performance trials comprised 15 min of submaximal steady-state exercise at 60% maximum work rate and a 16.1-km TT. The second and third trials were preceded by ingestion of either 70 mL of BR or nitrate-depleted BR (PLA) 3 h before exercise.

Results: Plasma nitrate (PLA, 39.1 ± 3.5 µM; BR, 150.5 ± 9.3 µM) and nitrite (PLA, 289.8 ± 27.9 nM; BR, 678.1 ± 103.5 nM) measured immediately before exercise were higher after ingestion of BR compared with that after PLA (P < 0.001, P = 0.004). V˙O2 during steady-state exercise was lower in the BR trial (2542 ± 114 mL·min−1) than that in the PLA trial (2727 ± 85 mL·min−1, P = 0.049). TT performance was significantly faster after BR (1664 ± 14 s) than that after PLA (1702 ± 15 s, P = 0.021).

Conclusion: A single dose of BR lowered V˙O2 during submaximal exercise and enhanced TT performance of trained cyclists in normobaric hypoxia. Consequently, ingestion of BR may be a practical and effective ergogenic aid for endurance exercise at altitude.

Author Information

1Institute for Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, Scotland, UNITED KINGDOM; 2School of Life Sciences, Kingston University, Kingston upon Thames, England, UNITED KINGDOM; 3School of Sport, Health and Applied Science, St Mary’s University College, Twickenham, England, UNITED KINGDOM; and 4Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff, Wales, UNITED KINGDOM

Address for correspondence: Chris Easton, B.Sc., Ph.D., FHEA, Institute for Clinical Exercise and Health Science, University of the West of Scotland, Almada Street, Hamilton ML3 0JB, Scotland, United Kingdom; E-mail: chris.easton@uws.ac.uk.

Submitted for publication January 2013.

Accepted for publication June 2013.

© 2014 American College of Sports Medicine