title: Acute administration of inorganic nitrate reduces VO(2peak) in endurance athletes.
abstract: OBJECTIVE
  Humans can reduce inorganic nitrate (NO(3)(-)) to nitrite (NO(2)(-)), nitric oxide (NO), and other bioactive nitrogen oxides. The purpose of this study was to test the hypothesis that a single dose of inorganic nitrate before exercise might enhance the tolerance of endurance athletes to high intensity exercise.
  
  
  METHODS
  Eleven cyclists (age = 34.3 ± 4.8 yr, VO(2peak) = 65.1 ± 6.2 mL·kg(-1)·min(-1)) participated in this randomized, double-blind, crossover study. Subjects received dietary supplementation with nitrate (NaNO(3) 10 mg·kg(-1) of body mass) or a placebo (NaCl) 3 h before exercise. They then performed a cycle ergometer test that consisted of four 6-min submaximal workloads, corresponding to 2.0, 2.5, 3.0, and 3.5 W·kg(-1) of body mass, interspersed with 3 min of passive recovery. After a 5-min recovery period, subjects performed one incremental exercise test until exhaustion.
  
  
  RESULTS
  Plasma nitrate and nitrite were significantly higher (P < 0.05) 3 h after supplementation (nitrate = 250 ± 80 μM, nitrite = 2313 ± 157 nM) than after the placebo (nitrate = 29 ± 8 μM, nitrite = 1998 ± 206 nM) at resting conditions. Nitrate supplementation significantly reduced VO(2peak)(nitrate = 4.64 ± 0.35 L·min(-1), placebo = 4.82 ± 0.33 L·min(-1), P = 0.010) and the ratio between VO(2) and power at maximal intensity (nitrate = 11.2 ± 1.1 mL·min(-1)·W(-1), placebo = 11.8 ± 1.1 mL·min(-1)·W(-1), P = 0.031). This reduction of VO(2) occurred without changes in the time to exhaustion (nitrate = 416 ± 32 s, placebo = 409 ± 27 s) or in the maximal power (nitrate = 416 ± 29 W, placebo = 410 ± 28 W).
  
  
  CONCLUSIONS
  A single oral dose of inorganic nitrate acutely reduces VO(2peak)without compromising the maximal exercise performance.
authors.affiliation: National Institute of Physical Education-Barcelona, Research Group on Sport Sciences, University of Barcelona, Barcelona, Spain. raul.bescos@inefc.net
authors.forename: Raúl
authors.initials: R
authors.lastname: Bescós
authors.forename: Ferran A
authors.initials: FA
authors.lastname: Rodríguez
authors.forename: Xavier
authors.initials: X
authors.lastname: Iglesias
authors.forename: Miguel D
authors.initials: MD
authors.lastname: Ferrer
authors.forename: Elena
authors.initials: E
authors.lastname: Iborra
authors.forename: Antoni
authors.initials: A
authors.lastname: Pons
mesh_terms: D000328:Adult; D056352:Athletes; D054874:Athletic Performance / Q000502:physiology; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D005080:Exercise Test; D006801:Humans; D008297:Male; D009566:Nitrates / Q000008:administration & dosage* / Q000097:blood / Q000502:physiology; D009573:Nitrites / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects* / Q000502:physiology; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology
chemical_list: D009566:Nitrates; D009573:Nitrites