title: Acute dietary nitrate supplementation improves cycling time trial performance.
abstract: OBJECTIVE
  Dietary nitrate supplementation has been shown to reduce the O2 cost of submaximal exercise and to improve high-intensity exercise tolerance. However, it is presently unknown whether it may enhance performance during simulated competition. The present study investigated the effects of acute dietary nitrate supplementation on power output (PO), VO2, and performance during 4- and 16.1-km cycling time trials (TT).
  
  
  METHODS
  After familiarization, nine club-level competitive male cyclists were assigned in a randomized, crossover design to consume 0.5 L of beetroot juice (BR; containing ∼ 6.2 mmol of nitrate) or 0.5 L of nitrate-depleted BR (placebo, PL; containing ∼ 0.0047 mmol of nitrate), ∼ 2.5 h before the completion of a 4- and a 16.1-km TT.
  
  
  RESULTS
  BR supplementation elevated plasma [nitrite] (PL = 241 ± 125 vs BR = 575 ± 199 nM, P < 0.05). The VO2 values during the TT were not significantly different between the BR and PL conditions at any elapsed distance (P > 0.05), but BR significantly increased mean PO during the 4-km (PL = 279 ± 51 vs BR = 292 ± 44 W, P < 0.05) and 16.1-km TT (PL = 233 ± 43 vs BR = 247 ± 44 W, P < 0.01). Consequently, BR improved 4-km performance by 2.8% (PL = 6.45 ± 0.42 vs BR = 6.27 ± 0.35 min, P < 0.05) and 16.1-km performance by 2.7% (PL = 27.7 ± 2.1 vs BR = 26.9 ± 1.8 min, P < 0.01).
  
  
  CONCLUSIONS
  These results suggest that acute dietary nitrate supplementation with 0.5 L of BR improves cycling economy, as demonstrated by a higher PO for the same VO2 and enhances both 4- and 16.1-km cycling TT performance.
authors.affiliation: Sport and Health Sciences, College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, United Kingdom.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Lansley
authors.forename: Paul G
authors.initials: PG
authors.lastname: Winyard
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Bailey
authors.forename: Anni
authors.initials: A
authors.lastname: Vanhatalo
authors.forename: Daryl P
authors.initials: DP
authors.lastname: Wilkerson
authors.forename: Jamie R
authors.initials: JR
authors.lastname: Blackwell
authors.forename: Mark
authors.initials: M
authors.lastname: Gilchrist
authors.forename: Nigel
authors.initials: N
authors.lastname: Benjamin
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
mesh_terms: D054874:Athletic Performance / Q000502:physiology*; D001628:Beverages; D001642:Bicycling / Q000502:physiology*; D001794:Blood Pressure; D018592:Cross-Over Studies; D019587:Dietary Supplements; D006801:Humans; D008297:Male; D009566:Nitrates / Q000627:therapeutic use*; D009573:Nitrites / Q000097:blood; D055815:Young Adult
chemical_list: D009566:Nitrates; D009573:Nitrites