| Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. | |
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MedLine Citation:
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PMID: 19661447 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Pharmacological sodium nitrate supplementation has been reported to reduce the O2 cost of submaximal exercise in humans. In this study, we hypothesized that dietary supplementation with inorganic nitrate in the form of beetroot juice (BR) would reduce the O2 cost of submaximal exercise and enhance the tolerance to high-intensity exercise. In a double-blind, placebo (PL)-controlled, crossover study, eight men (aged 19-38 yr) consumed 500 ml/day of either BR (containing 11.2 +/- 0.6 mM of nitrate) or blackcurrant cordial (as a PL, with negligible nitrate content) for 6 consecutive days and completed a series of "step" moderate-intensity and severe-intensity exercise tests on the last 3 days. On days 4-6, plasma nitrite concentration was significantly greater following dietary nitrate supplementation compared with PL (BR: 273 +/- 44 vs. PL: 140 +/- 50 nM; P < 0.05), and systolic blood pressure was significantly reduced (BR: 124 +/- 2 vs. PL: 132 +/- 5 mmHg; P < 0.01). During moderate exercise, nitrate supplementation reduced muscle fractional O2 extraction (as estimated using near-infrared spectroscopy). The gain of the increase in pulmonary O2 uptake following the onset of moderate exercise was reduced by 19% in the BR condition (BR: 8.6 +/- 0.7 vs. PL: 10.8 +/- 1.6 ml.min(-1).W(-1); P < 0.05). During severe exercise, the O2 uptake slow component was reduced (BR: 0.57 +/- 0.20 vs. PL: 0.74 +/- 0.24 l/min; P < 0.05), and the time-to-exhaustion was extended (BR: 675 +/- 203 vs. PL: 583 +/- 145 s; P < 0.05). The reduced O2 cost of exercise following increased dietary nitrate intake has important implications for our understanding of the factors that regulate mitochondrial respiration and muscle contractile energetics in humans. |
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Authors:
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Stephen J Bailey; Paul Winyard; Anni Vanhatalo; Jamie R Blackwell; Fred J Dimenna; Daryl P Wilkerson; Joanna Tarr; Nigel Benjamin; Andrew M Jones |
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Publication Detail:
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Type: Journal Article; Randomized Controlled Trial Date: 2009-08-06 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 107 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2009 Oct |
Date Detail:
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Created Date: 2009-10-16 Completed Date: 2009-12-24 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1144-55 Citation Subset: IM |
Affiliation:
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Exeter Univ., Sport and Health Sciences, St. Luke's Campus, Heavitree Rd., Exeter, EX1 2LU UK. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Administration, Oral Adult Beta vulgaris* Beverages Bicycling Blood Pressure / drug effects Cross-Over Studies Dietary Supplements* Double-Blind Method Exercise* Exercise Tolerance / drug effects* Hemoglobins / metabolism Humans Male Muscle Contraction* Muscle Fatigue / drug effects Muscle, Skeletal / drug effects*, metabolism Nitrites / administration & dosage*, blood Oxygen Consumption / drug effects* Oxyhemoglobins / metabolism Plant Preparations / administration & dosage* Plant Roots Spectroscopy, Near-Infrared Time Factors Young Adult |
| Chemical | |
Reg. No./Substance:
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0/Hemoglobins; 0/Nitrites; 0/Oxyhemoglobins; 0/Plant Preparations; 9008-02-0/deoxyhemoglobin |
| Comments/Corrections | |
Comment In:
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J Appl Physiol. 2009 Nov;107(5):1677; author reply 1678
[PMID:
19890035
]
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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