Effects of 7 days of arginine-alpha-ketoglutarate supplementation on blood flow, plasma L-arginine, nitric oxide metabolites, and asymmetric dimethyl arginine after resistance exercise.
ABSTRACT 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.
Twenty-four physically active men underwent 7 days of AAKG supplementation with 12 g/day of either NO(2) 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).
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 NO(2) 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 NO(2) group (p = .03).
NO(2) 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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ABSTRACT: With regular practice, resistance exercise can lead to gains in skeletal muscle mass by means of hypertrophy. The process of skeletal muscle fiber hypertrophy comes about as a result of the confluence of positive muscle protein balance and satellite cell addition to muscle fibers. Positive muscle protein balance is achieved when the rate of new muscle protein synthesis (MPS) exceeds that of muscle protein breakdown (MPB). While resistance exercise and postprandial hyperaminoacidemia both stimulate MPS, it is through the synergistic effects of these two stimuli that a net gain in muscle proteins occurs and muscle fiber hypertrophy takes place. Current evidence favors the post-exercise period as a time when rapid hyperaminoacidemia promotes a marked rise in the rate of MPS. Dietary proteins with a full complement of essential amino acids and high leucine contents that are rapidly digested are more likely to be efficacious in this regard. Various other compounds have been added to complete proteins, including carbohydrate, arginine and glutamine, in an attempt to augment the effectiveness of the protein in stimulating MPS (or suppressing MPB), but none has proved particularly effective. Evidence points to a higher protein intake in combination with resistance exercise as being efficacious in allowing preservation, and on occasion increases, in skeletal muscle mass with dietary energy restriction aimed at the promotion of weight loss. The goal of this review is to examine practices of protein ingestion in combination with resistance exercise that have some evidence for efficacy and to highlight future areas for investigation.05/2014; 44 Suppl 1:71-7. DOI:10.1007/s40279-014-0152-3
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ABSTRACT: It has been hypothesized that l-arginine improves exercise performance by increasing nitric oxide synthesis and levels of insulin and growth hormone (GH). Metabolic and hormonal responses to chronic l-arginine supplementation may clarify the mechanisms underlying its putative physiologic effects on physical performance. Therefore, the aim of this study was to investigate the effects that 4 weeks of supplementation with l-arginine would have on metabolic and hormonal parameters at rest and in response to exercise. Fifteen healthy runners were divided into treatment (ARG; 6 g l-arginine) and placebo (PLA; 6 g cornstarch) groups. On the first visit, blood samples were collected for baseline, and the supplement or placebo was provided. After 4 weeks of supplementation (second visit), blood samples were collected at the following intervals: at rest, immediately after the first 5-km time-trial running test (5km-TT), immediately after the second 5km-TT, and after 20 minutes of recovery (+20). In addition to exercise performance (total running time), plasma nitrate, nitrite, nitrate plus nitrite, cyclic guanosine monophosphate, lactate, ammonia and serum insulin, GH, insulin-like growth factor 1, and cortisol concentrations were evaluated. There were significant increases in plasma nitrite, cyclic guanosine monophosphate, lactate, ammonia and serum GH, and cortisol at the first 5km-TT, immediately after the second 5km-TT, and +20 in both ARG and PLA. Nitrate plus nitrite and nitrate increased only at +20. No significant change was observed in serum insulin and insulin-like growth factor 1 in any sample period. Total running time did not differ significantly between the 2 tests, in either ARG or PLA. Thus, according to our results, 4 weeks of l-arginine supplementation did not cause beneficial changes in metabolic and hormonal parameters, beyond those achieved with exercise alone.Nutrition research 10/2014; 34(1):31-9. DOI:10.1016/j.nutres.2013.10.006 · 2.59 Impact Factor