title: Influence of dietary nitrate supplementation on physiological and cognitive responses to incremental cycle exercise.
abstract: Dietary inorganic nitrate supplementation causes physiological effects which may enhance exercise tolerance. However it is not known whether nitrate might alter cognitive function during exercise. In a double-blind, cross-over study, sixteen subjects ingested either nitrate-rich beetroot juice or a placebo and completed a continuous cycle exercise test involving 20min stages at 50% and 70% V˙O2peak and a final stage at 90% V˙O2peak until volitional exhaustion. Cognitive tasks were completed before, during and after exercise. In the dietary nitrate condition: plasma [nitrite] increased (p<0.01), systolic blood pressure decreased (p<0.05) and there was a trend for a reduced oxygen uptake at 50% V˙O2peak. Tissue oxygenation improved across exercise intensities and exercise tolerance was greater at 90% V˙O2peak (p<0.05). Rating of perceived exertion, energy levels and cognitive performance were similar between conditions with mental fatigue being evident from 70% V˙O2peak onwards (p<0.05). Dietary nitrate supplementation enhanced short-term endurance exercise performance with concomitant mental fatigue but did not improve cognitive performance post-fatigue.
authors.affiliation: University of Canberra, Canberra, ACT 2601, Australia. Electronic address: kevin.thompson@canberra.edu.au.
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Thompson
authors.affiliation: Northumbria University, Newcastle NE18ST, UK.
authors.forename: Louise
authors.initials: L
authors.lastname: Turner
authors.affiliation: Northumbria University, Newcastle NE18ST, UK.
authors.forename: Jonathon
authors.initials: J
authors.lastname: Prichard
authors.affiliation: Northumbria University, Newcastle NE18ST, UK.
authors.forename: Fiona
authors.initials: F
authors.lastname: Dodd
authors.affiliation: Northumbria University, Newcastle NE18ST, UK.
authors.forename: David O
authors.initials: DO
authors.lastname: Kennedy
authors.affiliation: Northumbria University, Newcastle NE18ST, UK.
authors.forename: Crystal
authors.initials: C
authors.lastname: Haskell
authors.affiliation: University of Exeter, Exeter EX12LU, UK.
authors.forename: James R
authors.initials: JR
authors.lastname: Blackwell
authors.affiliation: University of Exeter, Exeter EX12LU, UK.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
mesh_terms: D027461:Beta vulgaris; D001642:Bicycling; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D005222:Mental Fatigue / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000502:physiology; D009566:Nitrates / Q000378:metabolism*; D009573:Nitrites / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D018517:Plant Roots; D012146:Rest / Q000502:physiology; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D055815:Young Adult
chemical_list: D009566:Nitrates; D009573:Nitrites
keywords: Cognitive function; Dietary nitrate; Exercise tolerance