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Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate

B. C. Breese, M. A. McNarry, S. Marwood, J. R. Blackwell, S. J. Bailey, A. M. Jones, Melitta McNarry Orcid Logo

AJP: Regulatory, Integrative and Comparative Physiology, Volume: 305, Issue: 12, Pages: R1441 - R1450

Swansea University Author: Melitta McNarry Orcid Logo

DOI (Published version): 10.1152/ajpregu.00295.2013

Abstract

Recent research has suggested that dietary nitrate (NO3-) supplementation might alter the physiological responses to exercise via specific effects on type II muscle. Severe-intensity exercise initiated from an elevated metabolic rate would be expected to enhance the proportional activation of higher...

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Published in: AJP: Regulatory, Integrative and Comparative Physiology
Published: 2013
URI: https://cronfa.swan.ac.uk/Record/cronfa26155
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spelling 2018-03-14T13:44:04.1628310 v2 26155 2016-02-11 Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate 062f5697ff59f004bc8c713955988398 0000-0003-0813-7477 Melitta McNarry Melitta McNarry true false 2016-02-11 STSC Recent research has suggested that dietary nitrate (NO3-) supplementation might alter the physiological responses to exercise via specific effects on type II muscle. Severe-intensity exercise initiated from an elevated metabolic rate would be expected to enhance the proportional activation of higher-order (type II) muscle fibers. The purpose of this study was therefore to test the hypothesis that, compared to placebo (PL), NO3--rich beetroot juice (BR) supplementation would speed the phase II o2 kinetics (τp) and enhance exercise tolerance during severe-intensity exercise initiated from a baseline of moderate-intensity exercise. Nine healthy, physically-active subjects were assigned in a randomized, double-blind, crossover design to receive BR (140 mL/day, containing ~8 mmol of NO3-) and PL (140 mL/day, containing ~0.003 mmol of NO3-) for 6 days. On days 4, 5 and 6 of the supplementation periods, subjects completed a double-step exercise protocol that included transitions from unloaded-to-moderate intensity exercise (U→M) followed immediately by moderate-to-severe-intensity exercise (M→S). Compared to PL, BR elevated resting plasma nitrite concentration (PL: 65 ± 32 vs. BR: 348 ± 170 nM, P<0.01) and reduced the o2 τp in M→S (PL: 46 ± 13 vs. BR: 36 ± 10 s, P<0.05) but not U→M (PL: 25 ± 4 vs. BR: 27 ± 6 s, P>0.05). During M→S exercise, the faster o2 kinetics coincided with faster NIRS-derived muscle [deoxyhemoglobin] kinetics (τ; PL: 20 ± 9 vs. BR: 10 ± 3 s, P<0.05) and a 22% greater time-to-task failure (PL: 521 ± 158 vs. BR: 635 ± 258 s, P<0.05). Dietary supplementation with NO3--rich BR juice speeds o2 kinetics and enhances exercise tolerance during severe-intensity exercise when initiated from an elevated metabolic rate. Journal Article AJP: Regulatory, Integrative and Comparative Physiology 305 12 R1441 R1450 nitric oxide, muscle oxygenation, fatigue, phase II time constant, motor unit recruitment. 15 12 2013 2013-12-15 10.1152/ajpregu.00295.2013 COLLEGE NANME Sport and Exercise Sciences COLLEGE CODE STSC Swansea University 2018-03-14T13:44:04.1628310 2016-02-11T10:49:55.5676279 Faculty of Science and Engineering School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Sport and Exercise Sciences B. C. Breese 1 M. A. McNarry 2 S. Marwood 3 J. R. Blackwell 4 S. J. Bailey 5 A. M. Jones 6 Melitta McNarry 0000-0003-0813-7477 7 0026155-14032018133843.pdf 26155.pdf 2018-03-14T13:38:43.9670000 Output 629257 application/pdf Accepted Manuscript true 2016-03-29T00:00:00.0000000 true eng
title Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate
spellingShingle Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate
Melitta McNarry
title_short Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate
title_full Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate
title_fullStr Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate
title_full_unstemmed Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate
title_sort Beetroot juice supplementation speeds O2 uptake kinetics and improves exercise tolerance during severe-intensity exercise initiated from an elevated metabolic rate
author_id_str_mv 062f5697ff59f004bc8c713955988398
author_id_fullname_str_mv 062f5697ff59f004bc8c713955988398_***_Melitta McNarry
author Melitta McNarry
author2 B. C. Breese
M. A. McNarry
S. Marwood
J. R. Blackwell
S. J. Bailey
A. M. Jones
Melitta McNarry
format Journal article
container_title AJP: Regulatory, Integrative and Comparative Physiology
container_volume 305
container_issue 12
container_start_page R1441
publishDate 2013
institution Swansea University
doi_str_mv 10.1152/ajpregu.00295.2013
college_str Faculty of Science and Engineering
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hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Sport and Exercise Sciences{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Sport and Exercise Sciences
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description Recent research has suggested that dietary nitrate (NO3-) supplementation might alter the physiological responses to exercise via specific effects on type II muscle. Severe-intensity exercise initiated from an elevated metabolic rate would be expected to enhance the proportional activation of higher-order (type II) muscle fibers. The purpose of this study was therefore to test the hypothesis that, compared to placebo (PL), NO3--rich beetroot juice (BR) supplementation would speed the phase II o2 kinetics (τp) and enhance exercise tolerance during severe-intensity exercise initiated from a baseline of moderate-intensity exercise. Nine healthy, physically-active subjects were assigned in a randomized, double-blind, crossover design to receive BR (140 mL/day, containing ~8 mmol of NO3-) and PL (140 mL/day, containing ~0.003 mmol of NO3-) for 6 days. On days 4, 5 and 6 of the supplementation periods, subjects completed a double-step exercise protocol that included transitions from unloaded-to-moderate intensity exercise (U→M) followed immediately by moderate-to-severe-intensity exercise (M→S). Compared to PL, BR elevated resting plasma nitrite concentration (PL: 65 ± 32 vs. BR: 348 ± 170 nM, P<0.01) and reduced the o2 τp in M→S (PL: 46 ± 13 vs. BR: 36 ± 10 s, P<0.05) but not U→M (PL: 25 ± 4 vs. BR: 27 ± 6 s, P>0.05). During M→S exercise, the faster o2 kinetics coincided with faster NIRS-derived muscle [deoxyhemoglobin] kinetics (τ; PL: 20 ± 9 vs. BR: 10 ± 3 s, P<0.05) and a 22% greater time-to-task failure (PL: 521 ± 158 vs. BR: 635 ± 258 s, P<0.05). Dietary supplementation with NO3--rich BR juice speeds o2 kinetics and enhances exercise tolerance during severe-intensity exercise when initiated from an elevated metabolic rate.
published_date 2013-12-15T03:31:17Z
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