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Ozcan Esen, Ceri Nicholas, Mike Morris and Stephen J. Bailey

Dietary supplementation with inorganic nitrate (NO 3 − ) has emerged as a popular nutritional intervention to enhance exercise performance. After ingestion, NO 3 − is chemically reduced to nitrite (NO 2 − ), via anaerobic bacteria that populate the oral cavity, and subsequently to nitric oxide (NO

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Jaqueline P. Batista, Igor M. Mariano, Tállita C.F. Souza, Juliene G. Costa, Jéssica S. Giolo, Nádia C. Cheik, Foued S. Espindola, Sarah Everman and Guilherme M. Puga

and salivary nitrite responses after an acute mat Pilates exercise session compared with an aerobic and a resistance exercise session. Methods Design The study consisted of participation in four acute sessions performed on alternate days in random order and in crossover design. The sessions consisted

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Edgar J. Gallardo and Andrew R. Coggan

Numerous studies in recent years have investigated the effects of dietary nitrate (NO 3 − ) on the physiological responses to, and/or performance during, exercise. This interest stems from the fact that dietary NO 3 − is an important source of nitric oxide (NO) via the “reverse” NO 3 −  → nitrite

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Jean M. Nyakayiru, Kristin L. Jonvik, Philippe J.M. Pinckaers, Joan Senden, Luc J.C. van Loon and Lex B. Verdijk

While the majority of studies reporting ergogenic effects of dietary nitrate have used a multiday supplementation protocol, some studies suggest that a single dose of dietary nitrate before exercise can also improve subsequent performance. We aimed to compare the impact of acute and 6-day sodium nitrate supplementation on oxygen uptake (V̇O2) and time-trial performance in trained cyclists. Using a randomized, double-blind, cross-over design, 17 male cyclists (25 ± 4 y, V̇O2peak 65 ± 4 ml·kg-1·min-1, Wmax 411 ± 35 W) were subjected to 3 different trials; 5 days placebo and 1 day sodium nitrate supplementation (1-DAY); 6 days sodium nitrate supplementation (6-DAY); 6 days placebo supplementation (PLA). Nitrate was administered as 1097 mg sodium nitrate providing 800 mg (~12.9 mmol) nitrate per day. Three hours after ingestion of the last supplemental bolus, indirect calorimetry was performed while subjects performed 30 min of exercise at 45% Wmax and 30 min at 65% Wmax on a cycle ergometer, followed by a 10 km time-trial. Immediately before exercise, plasma [nitrate] and [nitrite] increased to a similar extent during the 6-DAY and 1-DAY trial, but not with PLA (plasma nitrite: 501 ± 205, 553 ± 278, and 239 ± 74 nM, respectively; p < .001). No differences were observed between interventions in V̇O2 during submaximal exercise, or in time to complete the time-trial (6-DAY: 1004 ± 61, 1-DAY: 1022 ± 72, PLA: 1017 ± 71 s; p = .28). We conclude that both acute and 6-days of sodium nitrate supplementation do not alter V̇O2 during submaximal exercise or improve time-trial performance in highly trained cyclists, despite increasing plasma [nitrate] and [nitrite].

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Kristin L. Jonvik, Jan-Willem van Dijk, Joan M.G. Senden, Luc J.C. van Loon and Lex B. Verdijk

Over the past decade, the use of dietary nitrate to enhance performance has received increased attention, with possible ergogenic effects being caused by the reduction of dietary nitrate into nitrite and nitric oxide ( Lundberg et al., 2008 ). Nitric oxide plays a key role in skeletal muscle

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Philippe Richard, Lymperis P. Koziris, Mathieu Charbonneau, Catherine Naulleau, Jonathan Tremblay and François Billaut

). Similar changes were observed for salivary [nitrite] before the first (5261.7 [2005.0] μM vs 1467.8 [911.7] μM; ES: 1.73; 90% CL, 1.11 to 2.35; 100%/0%/0%) and second (5534.7 [2744.0] μM vs 1598.8 [887.1] μM; ES: 1.78; 90% CL, 1.32 to 2.24; 100%/0%/0%) time trials. Figure 1 —Changes in salivary nitrate

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Joseph A. McQuillan, Julia R. Casadio, Deborah K. Dulson, Paul B. Laursen and Andrew E. Kilding

. PubMed doi:10.1007/s00421-010-1818-7 10.1007/s00421-010-1818-7 21222130 10. Govoni M , Jansson EA , Weitzberg E , Lundberg JO . The increase in plasma nitrite after a dietary nitrate load is markedly attenuated by an antibacterial mouthwash . Nitric Oxide . 2008 ; 19(4) : 333 – 337 . PubMed

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Antoni Sureda, Miguel D. Ferrer, Antonia Mestre, Josep A. Tur and Antoni Pons

The authors studied the effects of antioxidant diet supplementation with an almond-based beverage on neutrophil antioxidants, nitrite, and protein oxidative alterations after exercise. Fourteen trained male amateur runners were randomly assigned in a double-blind fashion to receive antioxidant supplementation (152 mg/d vitamin C and 50 mg/d vitamin E) or placebo using an almond-based beverage for 1 mo and participated in a half-marathon race. Blood samples were taken before and after the half-marathon and after 3 hr recovery. Supplementation significantly increased basal neutrophil vitamin C compared with placebo (p < .05). Exercise increased neutrophil vitamin E levels in the supplemented group and decreased vitamin C in both groups after recovery (p < .05). Neutrophil catalase and glutathione peroxidase gene expression and nitrite levels were significantly increased as result of exercise (p < .05). Nitrotyrosine and protein carbonyl derivates increased only in the placebo group after exercise (p < .05), and these values remained high at recovery. No significant differences were evidenced in caspase-3 activity and DNA damage. Antioxidant supplementation with vitamins C and E reduced the exercise-induced oxidation of proteins in neutrophils, without altering the antioxidant adaptive response, as evidenced by the increased catalase and glutathione peroxidase gene expression.

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David J. Muggeridge, Christopher C. F. Howe, Owen Spendiff, Charles Pedlar, Philip E. James and Chris Easton

The aim of the current study was to determine the effects of dietary nitrate ingestion on parameters of submaximal and supramaximal exercise and time trial (TT) performance in trained kayakers. Eight male kayakers completed four exercise trials consisting of an initial discontinuous graded exercise test to exhaustion and three performance trials using a kayak ergometer. The performance trials were composed of 15 min of paddling at 60% of maximum work rate, five 10-s all-out sprints, and a 1 km TT. The second and third trials were preceded by ingestion of either 70 ml nitrate-rich concentrated beetroot juice (BR) or tomato juice (placebo [PLA]) 3 hr before exercise using a randomized crossover design. Plasma nitrate (PLA: 33.8 ± 1.9 μM, BR: 152 ± 3.5 μM) and nitrite (PLA: 519.8 ± 25.8, BR: 687.9 ± 20 nM) were higher following ingestion of BR compared with PLA (both p < .001). VO2 during steady-state exercise was lower in the BR trial than in the PLA trial (p = .010). There was no difference in either peak power in the sprints (p = .590) or TT performance between conditions (PLA: 277 ± 5 s, BR: 276 ± 5 s, p = .539). Despite a reduction in VO2, BR ingestion appears to have no effect on repeated supramaximal sprint or 1 km TT kayaking performance. A smaller elevation in plasma nitrite following a single dose of nitrate and the individual variability in this response may partly account for these findings.

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Marcus J. Callahan, Evelyn B. Parr, John A. Hawley and Louise M. Burke

When ingested alone, beetroot juice and sodium bicarbonate are ergogenic for high-intensity exercise performance. This study sought to determine the independent and combined effects of these supplements. Eight endurance trained (VO2max 65 mL·kg·min-1) male cyclists completed four × 4-km time trials (TT) in a doubleblind Latin square design supplementing with beetroot crystals (BC) for 3 days (15 g·day-1 + 15 g 1 h before TT, containing 300 mg nitrate per 15 g), bicarbonate (Bi 0.3 g·kg-1 body mass [BM] in 5 doses every 15 min from 2.5 h before TT); BC+Bi or placebo (PLA). Subjects completed TTs on a Velotron cycle ergometer under standardized laboratory conditions. Plasma nitrite concentrations were significantly elevated only in the BC+Bi trial before the TT (1520 ± 786 nmol·L-1) compared with baseline (665 ± 535 nmol·L-1, p = .02) and the Bi and PLA conditions (Bi: 593 ± 203 nmol·L-1, p < .01; PLA: 543 ± 369 nmol·L-1, p < .01). Plasma nitrite concentrations were not elevated in the BC trial before the TT (1102 ± 218 nmol·L-1) compared with baseline (975 ± 607 nmol·L-1, p > .05). Blood bicarbonate concentrations were increased in the BC+Bi and Bi trials before the TT (BC+Bi: 30.9 ± 2.8 mmol·L-1; Bi: 31.7 ± 1.1 mmol·L-1). There were no differences in mean power output (386–394 W) or the time taken to complete the TT (335.8–338.1 s) between any conditions. Under the conditions of this study, supplementation was not ergogenic for 4-km TT performance.