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Kelsey H. Fisher-Wellman and Richard J. Bloomer

Background:

Carbohydrate powder in the form of maltodextrin is widely used by athletes for postexercise glycogen resynthesis. There is some concern that such a practice may be associated with a postprandial rise in reactive oxygen and nitrogen species production and subsequent oxidation of macromolecules. This is largely supported by findings of increased oxidative-stress biomarkers and associated endothelial dysfunction after intake of dextrose.

Purpose:

To compare the effects of isocaloric dextrose and maltodextrin meals on blood glucose, triglycerides (TAG), and oxidative-stress biomarkers in a sample of young healthy men.

Methods:

10 men consumed isocaloric dextrose and maltodextrin powder drinks (2.25 g/kg) in a random-order, crossover design. Blood samples were collected premeal (fasting) and at 1, 2, 4, and 6 hr postmeal and assayed for glucose, TAG, malondialdehyde, hydrogen peroxide, nitrate/nitrite, and Trolox-equivalent antioxidant capacity.

Results:

Significant meal effects were noted for glucose total area under the curve (p = .004), with values higher for the dextrose meal. No other statistically significant meal effects were noted (p > .05). With respect to the 2 (meal) × 5 (time) ANOVA, no significant interaction, time, or meal effects were noted for any variable (p > .05), with the exception of glucose, for which a main effect for both meal (p < .0001) and time (p = .0002) was noted.

Conclusions:

These data indicate that carbohydrate meals, consumed as either dextrose or maltodextrin, pose little postprandial oxidative insult to young, healthy men. As such, there should be minimal concern over such feedings, even at high dosages, assuming adequate glucose metabolism.

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Darryn S. Willoughby, Tony Boucher, Jeremy Reid, Garson Skelton and Mandy Clark

Background:

Arginine-alpha-ketoglutarate (AAKG) supplements are alleged to increase nitric oxide production, thereby resulting in vasodilation during resistance exercise. This study sought to determine the effects of AAKG supplementation on hemodynamics and brachial-artery blood flow and the circulating levels of L-arginine, nitric oxide metabolites (NOx; nitrate/nitrite), asymmetric dimethyl arginine (ADMA), and L-arginine:ADMA ratio after resistance exercise.

Methods:

Twenty-four physically active men underwent 7 days of AAKG supplementation with 12 g/day of either NO2 Platinum or placebo (PLC). Before and after supplementation, a resistance-exercise session involving the elbow flexors was performed involving 3 sets of 15 repetitions with 70–75% of 1-repetition maximum. Data were collected immediately before, immediately after (PST), and 30 min after (30PST) each exercise session. Data were analyzed with factorial ANOVA (p < .05).

Results:

Heart rate, blood pressure, and blood flow were increased in both groups at PST (p = .001) but not different between groups. Plasma L-arginine was increased in the NO2 group (p = .001). NOx was shown to increase in both groups at PST (p = .001) and at 30PST (p = .001) but was not different between groups. ADMA was not affected between tests (p = .26) or time points (p = .31); however, the L-arginine:ADMA ratio was increased in the NO2 group (p = .03).

Conclusion:

NO2 Platinum increased plasma L-arginine levels; however, the effects observed in hemodynamics, brachial-artery blood flow, and NOx can only be attributed to the resistance exercise.

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Seiji Maeda, Asako Zempo-Miyaki, Hiroyuki Sasai, Takehiko Tsujimoto, Rina So and Kiyoji Tanaka

Obesity and increased arterial stiffness are independent risk factors for cardiovascular disease. Arterial stiffness is increased in obese individuals than in age-matched nonobese individuals. We demonstrated that dietary modification and exercise training are effective in reducing arterial stiffness in obese persons. However, the differences in the effect on arterial stiffness between dietary modification and exercise training are unknown. The purpose of the current study was to compare the effect of dietary modification and aerobic exercise training on arterial stiffness and endothelial function in overweight and obese persons. Forty-five overweight and obese men (48 ± 1 year) completed either a dietary modification (well-balanced nutrient, 1680 kcal/day) or an exercise-training program (walking, 40–60 min/day, 3 days/week) for 12 weeks. Before and after the intervention, all participants underwent anthropometric measurements. Arterial stiffness was measured based on carotid arterial compliance, brachial-ankle pulse wave velocity (baPWV), and endothelial function was determined by circulating level of endothelin-1 (ET-1) and nitric oxide metabolite (nitrites/nitrate as metabolite: NOx). Body mass and waist circumference significantly decreased after both intervention programs. Weight loss was greater after dietary modification than after exercise training (-10.1 ± 0.6 kg vs. -3.6 ± 0.5 kg, p < .01). Although arterial stiffness and the plasma levels of ET-1 and NOx were improved after dietary modification or exercise training, there were no differences in those improvements between the 2 types of interventions. Exercise training improves arterial function in obese men without as much weight loss as after dietary modification.

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Trent Stellingwerff, Ingvill Måkestad Bovim and Jamie Whitfield

before the warm-up athletes should aim to drink 400–600 ml water or sports drink. Timing of prerace snacks and ergogenic aids are important. Eat last meal 1–4 hr prior the warm-up. And follow the guidelines for caffeine, bicarbonate, or nitrate as discussed in this paper. Race tactics is crucial for

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Emma M. Crum, Matthew J. Barnes and Stephen R. Stannard

accompanied by increased postexercise blood flow. The results of this study linked findings from previous investigations involving beetroot juice (BRJ). Both POMx and BRJ contain significant concentrations of nitrates (NO 3 − ), a precursor to the powerful vasodilator and signaling compound, nitric oxide (NO

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Louise M. Burke and Peter Peeling

, 2008 ; Conger et al., 2011 ; Glaister & Gissaine, 2017 ), including its specific delivery in energy drinks ( Souza et al., 2017 ), bicarbonate ( Carr et al., 2011b ), creatine ( Branch, 2003 ; Mujika & Padilla, 1997 ), b-alanine ( Hobson et al., 2012 ; Saunders et al., 2016 ), nitrate

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Tiago Turnes, Rogério S.O. Cruz, Fabrizio Caputo and Rafael A. De Aguiar

rowing performance such as beta-alanine, which enhances muscle carnosine, one of the determinants of rowing performance, 16 creatine, and inorganic nitrate. Furthermore, because rowing is a weight-category sport performed under environmental conditions, providing information about the influence of

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International Olympic Committee Expert Group on Dietary Supplements in Athletes

agents and nitrate. Benefits may be mediated by addressing the physiological factors that limit performance in a specific sporting scenario and/or by effects on the central nervous system. Because responses seem to vary between individuals and depend on the exercise model used, supplements should be

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Blair Crewther, Konrad Witek, Paweł Draga, Piotr Zmijewski and Zbigniew Obmiński

was replicated in subfertile men ( D’Aniello et al., 2012 ) and a subgroup of middle-aged men using DAA mixed with nitrate and vitamin D ( Bloomer et al., 2015 ). However, in physically-trained men, taking DAA or a DAA-mixed supplement over 14- or 28-day periods (at 3 g/day or less) when combined with

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Austin T. Robinson, Adriana Mazzuco, Ahmad S. Sabbahi, Audrey Borghi-Silva and Shane A. Phillips

multi-ingredient dietary preworkout supplement investigated contained a number of prodilatory compounds (e.g., nitrate and ascorbic acid), it would not adversely affect postacute exercise CV function in these recreationally active young adults. Methods Experimental Approach Testing sessions for each