title: Dietary nitrate supplementation enhances short but not longer duration running time-trial performance.
abstract: OBJECTIVE
  This study evaluated the effects of dietary nitrate (NO3-) supplementation on physiological functioning and exercise performance in trained runners/triathletes conducting short and longer-distance treadmill running time-trials (TT).
  
  
  METHODS
  Eight trained male runners or triathletes completed four exercise performance tests comprising a 10 min warm up followed by either a 1500 or 10,000 m treadmill TT. Exercise performance tests were preceded 3 h before the exercise by supplementation with either 140 ml concentrated nitrate-rich (~12.5 mmol nitrate) (BRJ) or nitrate-deplete (~0.01 mmol nitrate) (PLA) beetroot juice.
  
  
  RESULTS
  BRJ supplementation significantly elevated plasma [NO2-] (P < 0.05). Resting blood pressure and exercise [Formula: see text] were not significantly different between BRJ and PLA (P > 0.05). However, post-exercise blood [lactate] was significantly greater in BRJ following the 1500 m TT (6.6 ± 1.2 vs. 6.1 ± 1.5 mM; P < 0.05), but not significantly different between conditions in the 10,000 m TT (P > 0.05). Performance in the 1500 m TT was significantly faster in BRJ vs. PLA (319.6 ± 36.2 vs. 325.7 ± 38.8 s; P < 0.05). Conversely, there was no significant difference in 10,000 m TT performance between conditions (2643.1 ± 324. 1 vs. 2649.9 ± 319.8 s, P > 0.05).
  
  
  CONCLUSIONS
  Acute BRJ supplementation significantly enhanced 1500 m, but not 10,000 m TT performance. These findings suggest that BRJ might be ergogenic during shorter distance TTs which allow for a high work rate, but not during longer distance TTs, completed at a lower work rate.
authors.affiliation: Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett University, Leeds, LS163QS, UK. O.Shannon@LeedsBeckett.ac.uk.
authors.forename: Oliver Michael
authors.initials: OM
authors.lastname: Shannon
authors.affiliation: Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett University, Leeds, LS163QS, UK.
authors.forename: Matthew John
authors.initials: MJ
authors.lastname: Barlow
authors.affiliation: Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett University, Leeds, LS163QS, UK.
authors.forename: Lauren
authors.initials: L
authors.lastname: Duckworth
authors.affiliation: Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett University, Leeds, LS163QS, UK.
authors.forename: Emily
authors.initials: E
authors.lastname: Williams
authors.affiliation: Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett University, Leeds, LS163QS, UK.
authors.forename: Georgina
authors.initials: G
authors.lastname: Wort
authors.affiliation: Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett University, Leeds, LS163QS, UK.|Defence Medical Services, Royal Centre for Defence Medicine, Birmingham, B152TH, UK.
authors.forename: David
authors.initials: D
authors.lastname: Woods
authors.affiliation: Institute of Cellular Medicine, University of Newcastle, Newcastle upon Tyne, NE45PL, UK.
authors.forename: Mario
authors.initials: M
authors.lastname: Siervo
authors.affiliation: Research Institute for Sport, Physical Activity, and Leisure, Leeds Beckett University, Leeds, LS163QS, UK.
authors.forename: John Paul
authors.initials: JP
authors.lastname: O'Hara
mesh_terms: D000328:Adult; D054874:Athletic Performance; D027461:Beta vulgaris / Q000737:chemistry; D001794:Blood Pressure / Q000187:drug effects; D019587:Dietary Supplements; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D012420:Running
chemical_list: D009566:Nitrates
keywords: Beetroot juice; Dietary supplementation; Exercise performance; Nitric oxide