Effects of Oral L-arginine Supplementation for a Week, on Changes in Respiratory Gases and Blood Lactate in Female Handballists

Nowadays, due to the epidemic of sports supplements, the effects of these supplements on athletic performance require analysis and evaluation. Therefore, the purpose of the present study is investigating the effect of weekly arginine supplementation on blood lactate concentration and metabolic parameters of respiratory in female athletes (handballists). The population of this quasi-experimental are sixteen female handballists, with the mean age of (2.49 ± 22.15 years), height of (5.85 ± 165.35 cm), and weight of (8.61 ± 59.94 kg), were selected on a voluntary basis. The samples were randomly divided into two groups of L-arginine (n = 8) and placebo (n = 8). The intervention group consumed 21 g L-arginine and the control consumed 21 g placebo (3 capsules of 1000 mg) daily for one week. Bruce test was taken from the participants in two stages with a one week interval. Data analysis was done using inferential statistics (paired t-test, independent t-test and repeated measures) and employing the SPSS software, version 21. For respiratory parameters, a significant decrease was observed in the respiratory exchange ratio, and significant increase was seen in oxygen consumption, carbon dioxide production, pulmonary ventilation, ventilatory equivalent ratio for oxygen and carbon dioxide, VO2 at the anaerobic threshold, and VO2 max for L-arginine group; however, changes in the ratio of VO2 at the anaerobic threshold and respiratory compensation point to oxygen consumption were not significant (p >0.05). Also in the L-arginine group, a significant decrease was observed in blood lactic acid concentration compared with the placebo group (p <0.05). The results of this research indicate that L-arginine delays anaerobic threshold and fatigue with changes in blood lactate concentration and metabolic parameters of the respiratory system. Likely, L-arginine supplement can be utilized to improve the athletes’ performance in sports activities.