Effects of Chronic Supplementation of L‐Arginine on Physical Fitness in Water Polo Players
Jessica Gambardella, Antonella Fiordelisi, L Spigno, Lorenzo Boldrini, Giulia Lungonelli, Eugenio Di Vaia, Gaetano Santulli, Daniela Sorriento, Federica Andrea Cerasuolo, Valentina Trimarco, Guido Iaccarino
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 (PGC1 α ) 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.