Publication Date

2014

Abstract

Purpose: Dietary nitrate supplementation with beetroot juice ( BR ) has received widespread attention as an ergogenic aid. However, recent evidence in well-trained cyclists has not consistently reported improved cycling economy or performance. The present study examined the effects of acute and chronic BR supplementation on V·O2 during submaximal running and 1500-m time trial ( TT ) performance of elite distance runners. Methods: Eight male 1500-m runners ( V·O2peak, 80 ± 5 mL·kg-1·min-1; 1500-m personal best, 3:56 ± 9 s ) participated in this study. In a randomized, double-blind, crossover design, subjects supplemented with BR or a nitrate-free BR placebo ( PL ) for 8 d separated by at least 1 wk. On days 1 ( acute ) and 8 ( chronic ), subjects ingested 210 mL of BR ( 19.5-mmol nitrate ) or PL and completed a submaximal treadmill run and 1500-m TT on an indoor 200-m track. Results: Plasma nitrate increased from 37 ± 15 to 615 ± 151 µM ( acute ) and 870 ± 259 µM ( chronic ) after BR supplementation. There were no V·O2 differences between conditions at 50%, 65%, and 80% V·O2peak ( acute PL, 4194 ± 90 mL·min-1; chronic PL, 4216 ± 95 mL·min-1; acute BR, 4192 ± 113 mL·min-1; chronic BR, 4299 ± 92 mL·min-1 ). The 1500-m TT was unaffected by acute or chronic BR supplementation ( acute PL, 4:10.4 min:s ± 2.5 s; chronic PL, 4:11.4 min:s ± 2.7 s; acute BR, 4:10.7 min:s ± 1.5 s; chronic BR, 4:10.5 min:s ± 2.2 s ). However, two subjects improved their TT performance after acute ( 5.8 and 5.0 s ) and chronic BR supplementation ( 7.0 and 0.5 s ). Conclusions: Acute and chronic BR supplementation did not reduce running V·O2 or improve 1500-m TT performance of a group of elite distance runners, but two responders to BR were identified.

School/Institute

Mary MacKillop Institute for Health Research

Document Type

Journal Article

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