Effects of Chronic Supplementation of L‐Arginine on Physical Fitness in Water Polo Players

Abstract

Background. Ergogenic nutritional supplementation is sought by professional athletes for improving physical performance; nevertheless, scientific evidence to support the chronic use of L-Arginine among water polo players is missing. Methods. Seventeen male professional water polo players were randomly assigned to assume 5 grams per day of L-Arginine ( n = 9 ) or placebo ( n = 8 ) for 4 weeks. The players’ fitness level was assessed in the maximal speed swimming test. Ear lobe blood samples taken before and after the effort for serum lactate content were analyzed. A speed-to-lactate ratio was generated at the baseline and after 4 weeks of treatment. We also tested the effects of L-Arginine in vitro, measuring NO production, mitochondrial respiration, and gene expression in human fibroblasts. Results. L-Arginine did not modify BMI, muscle strength, and maximal speed at 200 meters after 4 weeks. However, L-Arginine ameliorated oxidative metabolism to exercise as suggested by the statistically significant lower lactate-to-speed ratio, which was not observed in placebo-treated controls. In vitro, L-Arginine induced the expression of a key regulator of mitochondrial biogenesis (PGC1α) and genes encoding for complex I and increased the production of nitric oxide and the maximal oxygen consumption rate. Conclusions. Chronic L-Arginine is safe and effective in ameliorating the oxidative metabolism of professional water polo players, through a mechanism of enhanced mitochondrial function.

Effects of adding L-arginine orally to standard therapy in patients with COVID-19: A randomized, double-blind, placebo-controlled, parallel-group trial. Results of the first interim analysis

“…Thus, in order to assess the role of L-arginine supplementation in the reduction of respiratory support, we performed a multivariate analysis which demonstrated that treatment with Larginine was the main determinant of this phenomenon, ruling out the possibility that it could be merely due to the younger age of this group of patients. This conclusion is corroborated by the observation that L-arginine supplementation was the main determinant in the reduction of in-hospital stay duration; the in-hospital stay median (IQR 25 th ,75 th percentile) number of days was 46 (45,46) in the placebo group vs 25 (21,26) in the L-arginine group (p < 0.0001, Mann-Whitney); this finding was also confirmed after adjustment for potential confounders including age.…”

“…The formulation of Bioarginina Ò used in this study consists of oral vials containing 1.66 g of L-arginine, whose taste is fully buffered by the presence of sucrose and by an acidity regulator (anhydrous citric acid); therefore, there were no differences in appearance, smell, or taste between treatment and placebo. The dose was chosen based on a previous study proving that such a regimen was safe and significantly effective in ameliorating the oxidative metabolism of professional water polo players [21]. Respiratory support was defined as follows (from the more to the less intense one): NIV: non-invasive ventilation; CPAP: continuous positive airway pressure; HFNC: highflow nasal cannula; LTOT: Long-term oxygen therapy [22].…”

“…At 10-day evaluation, 71.1% of patients in the L-arginine arm and 44.4% in the placebo arm (p < 0.01) had the respiratory support reduced; however, a significant difference was not detected 20 days after randomization. Strikingly, patients treated with L-arginine exhibited a significantly reduced in-hospital stay vs placebo, with a median (interquartile range 25 th ,75 th percentile) of 46 days (45,46) in the placebo group vs 25 days (21,26) in the L-arginine group (p < 0.0001); these findings were also confirmed after adjusting for potential confounders including age, duration of symptoms, comorbidities, D-dimer, as well as antiviral and anticoagulant treatments. The other secondary outcomes were not significantly different between groups.…”

Oral L-Arginine (5 g/day) for 14 Days Improves Microcirculatory Function in Healthy Young Women and Healthy and Type 2 Diabetes Mellitus Elderly Women

“…Low plasma concentration of L-arginine results in impaired L-arginine-NO signaling and may promote endothelial dysfunction [32]. Also, L-arginine has been effective in decreasing oxidative metabolism in water polo players [33]. Another important carbohydrate-like substance, vitamin C, has an antioxidant effect and protects vascular endothelial function as well.…”

L-Arginine Improves Cognitive Impairment in Hypertensive Frail Older Adults

“…Patients were randomly assigned to the L-Arginine (Bioarginina ® , 1.66 g, twice a day) or placebo ( n = 37) parallel groups and followed-up for 4-weeks. The dose of L-Arginine was based on previously published clinical trials ( 33 , 34 ).…”