The Effect of Variable Doses of Inorganic Nitrate-Rich Beetroot Juice on Simulated 2000-m Rowing Performance in Trained Athletes

• Published in: International journal of sports physiology and performance 2014-07, Vol.9 (4), p.615-620
• Main Authors: Hoon, Matthew W., Jones, Andrew M., Johnson, Nathan A., Blackwell, Jamie R., Broad, Elizabeth M., Lundy, Bronwen, Rice, Anthony J., Burke, Louise M.
• Format: Article
• Language: English
• Subjects: Nitrates; Rowing
• ISSN: 1555-0265; 1555-0273
• DOI: 10.1123/ijspp.2013-0207

Context: Beetroot juice is a naturally rich source of inorganic nitrate (NO3−), a compound hypothesized to enhance endurance performance by improving exercise efficiency. Purpose: To investigate the effect of different doses of beetroot juice on 2000-m ergometer-rowing performance in highly trained athletes. Methods: Ten highly trained male rowers volunteered to participate in a placebo-controlled, double-blinded crossover study. Two hours before undertaking a 2000-m rowing-ergometer test, subjects consumed beetroot juice containing 0 mmol (placebo), 4.2 mmol (SINGLE), or 8.4 mmol (DOUBLE) NO3−. Blood samples were taken before supplement ingestion and immediately before the rowing test for analysis of plasma [NO3−] and [nitrite (NO2−)]. Results: The SINGLE dose demonstrated a trivial effect on time to complete 2000 m compared with placebo (mean difference: 0.2 ± 2.5 s). A possibly beneficial effect was found with DOUBLE compared with SINGLE (mean difference –1.8 ± 2.1 s) and with placebo (–1.6 ± 1.6 s). Plasma [NO2−] and [NO3−] demonstrated a dose-response effect, with greater amounts of ingested nitrate leading to substantially higher concentrations (DOUBLE > SINGLE > placebo). There was a moderate but insignificant correlation (r = –.593, P = .055) between change in plasma [NO2−] and performance time. Conclusion: Compared with nitratedepleted beetroot juice, a high (8.4 mmol NO3−) but not moderate (4.2 mmol NO3−) dose of NO3− in beetroot juice, consumed 2 h before exercise, may improve 2000-m rowing performance in highly trained athletes.