| Dietary nitrate supplementation enhances muscle contractile efficiency during knee-extensor exercise in humans. | |
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MedLine Citation:
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PMID: 20466802 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The purpose of this study was to elucidate the mechanistic bases for the reported reduction in the O(2) cost of exercise following short-term dietary nitrate (NO(3)(-)) supplementation. In a randomized, double-blind, crossover study, seven men (aged 19-38 yr) consumed 500 ml/day of either nitrate-rich beet root juice (BR, 5.1 mmol of NO(3)(-)/day) or placebo (PL, with negligible nitrate content) for 6 consecutive days, and completed a series of low-intensity and high-intensity "step" exercise tests on the last 3 days for the determination of the muscle metabolic (using (31)P-MRS) and pulmonary oxygen uptake (Vo(2)) responses to exercise. On days 4-6, BR resulted in a significant increase in plasma [nitrite] (mean +/- SE, PL 231 +/- 76 vs. BR 547 +/- 55 nM; P < 0.05). During low-intensity exercise, BR attenuated the reduction in muscle phosphocreatine concentration ([PCr]; PL 8.1 +/- 1.2 vs. BR 5.2 +/- 0.8 mM; P < 0.05) and the increase in Vo(2) (PL 484 +/- 41 vs. BR 362 +/- 30 ml/min; P < 0.05). During high-intensity exercise, BR reduced the amplitudes of the [PCr] (PL 3.9 +/- 1.1 vs. BR 1.6 +/- 0.7 mM; P < 0.05) and Vo(2) (PL 209 +/- 30 vs. BR 100 +/- 26 ml/min; P < 0.05) slow components and improved time to exhaustion (PL 586 +/- 80 vs. BR 734 +/- 109 s; P < 0.01). The total ATP turnover rate was estimated to be less for both low-intensity (PL 296 +/- 58 vs. BR 192 +/- 38 microM/s; P < 0.05) and high-intensity (PL 607 +/- 65 vs. BR 436 +/- 43 microM/s; P < 0.05) exercise. Thus the reduced O(2) cost of exercise following dietary NO(3)(-) supplementation appears to be due to a reduced ATP cost of muscle force production. The reduced muscle metabolic perturbation with NO(3)(-) supplementation allowed high-intensity exercise to be tolerated for a greater period of time. |
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Authors:
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Stephen J Bailey; Jonathan Fulford; Anni Vanhatalo; Paul G Winyard; Jamie R Blackwell; Fred J DiMenna; Daryl P Wilkerson; Nigel Benjamin; Andrew M Jones |
Publication Detail:
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Type: Journal Article; Randomized Controlled Trial Date: 2010-05-13 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 109 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2010 Jul |
Date Detail:
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Created Date: 2010-06-30 Completed Date: 2010-10-14 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: 135-48 Citation Subset: IM |
Affiliation:
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School of Sport and Health Sciences, University of Exeter, 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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Adult Beta vulgaris Beverages Dietary Supplements* Exercise / physiology* Humans Knee / physiology* Male Muscle Contraction / drug effects, physiology Muscle Strength / drug effects* Muscle, Skeletal / chemistry, drug effects* Nitrates / administration & dosage* Nitrites / analysis Oxygen Consumption / drug effects Phosphocreatine / analysis Pulmonary Ventilation / drug effects Young Adult |
| Chemical | |
Reg. No./Substance:
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0/Nitrates; 0/Nitrites; 67-07-2/Phosphocreatine |
| Comments/Corrections | |
Erratum In:
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J Appl Physiol. 2010 Sep;109(3):943 |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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