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Dietary Nitrate Supplementation Enhances Exercise Performance in Peripheral Arterial Disease

Kenjale, Aarti A, Ham, Katherine L, Stabler, Thomas, Robbins, Jennifer L, Johnson, Johanna L, VanBruggen, Mitch, Privette, Grayson, Yim, Eunji, Kraus, William E and Allen, Jason (2011) Dietary Nitrate Supplementation Enhances Exercise Performance in Peripheral Arterial Disease. Journal of Applied Physiology, 110 (6). pp. 1582-1591. ISSN 8750-7587 (print) 1522-1601 (online)

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Abstract

Peripheral arterial disease (PAD) results in a failure to adequately supply blood and oxygen (O2) to working tissues and presents as claudication pain during walking. Nitric oxide (NO) bioavailability is essential for vascular health and function. Plasma nitrite (NO2−) is a marker of vascular NO production but may also be a protected circulating “source” that can be converted to NO during hypoxic conditions, possibly aiding perfusion. We hypothesized that dietary supplementation of inorganic nitrate in the form of beetroot (BR) juice would increase plasma NO2− concentration, increase exercise tolerance, and decrease gastrocnemius fractional O2 extraction, compared with placebo (PL). This was a randomized, open-label, crossover study. At each visit, subjects (n = 8) underwent resting blood draws, followed by consumption of 500 ml BR or PL and subsequent blood draws prior to, during, and following a maximal cardiopulmonary exercise (CPX) test. Gastrocnemius oxygenation during the CPX was measured by near-infrared spectroscopy. There were no changes from rest for [NO2−] (152 ± 72 nM) following PL. BR increased plasma [NO2−] after 3 h (943 ± 826 nM; P ≤ 0.01). Subjects walked 18% longer before the onset of claudication pain (183 ± 84 s vs. 215 ± 99 s; P ≤ 0.01) and had a 17% longer peak walking time (467 ± 223 s vs. 533 ± 233 s; P ≤ 0.05) following BR vs. PL. Gastrocnemius tissue fractional O2 extraction was lower during exercise following BR (7.3 ± 6.2 vs. 10.4 ± 6.1 arbitrary units; P ≤ 0.01). Diastolic blood pressure was lower in the BR group at rest and during CPX testing (P ≤ 0.05). These findings support the hypothesis that NO2−-related NO signaling increases peripheral tissue oxygenation in areas of hypoxia and increases exercise tolerance in PAD

Item Type: Article
Uncontrolled Keywords: nitrite, nitric oxide, exercise, peripheral arterial disease
Subjects: FOR Classification > 1106 Human Movement and Sports Science
FOR Classification > 1111 Nutrition and Dietetics
Faculty/School/Research Centre/Department > College of Sports and Exercise Science
Depositing User: Ms Julie Gardner
Date Deposited: 24 Sep 2014 04:07
Last Modified: 24 Sep 2014 04:07
URI: http://vuir.vu.edu.au/id/eprint/25751
DOI: https://doi.org/10.1152/japplphysiol.00071.2011
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Citations in Scopus: 169 - View on Scopus

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