Introduction: Recovery after sports training especially endurance activities is one of the most important concerns of athletes and coaches. The present study aimed to investigate the effect of a short-term course of oral l-arginine supplementation on the sequence of responses of some biochemical indices levels during the recovery period in male endurance swimmers.
Methods: 20 male endurance swimmers with the mean and standard deviation of age: 29.25±4.5 years, weight: 78.06±7.5 Kg, BMI: 23.99±3.69 Kg/m², and VO_2max: 41±3.1 mL/kg.min were randomly assigned into two supplement (10 people) and placebo (10 people) groups. During one week, 7 g/day of L-arginine was given to the supplement group and 7 g/day of placebo was given to the other group. At the beginning and the end of the week, the participants underwent a 1500-meter freestyle swimming test. Blood sampling was drawn at the rest times and 5, 30, and 60 minutes after exercise.
Results: The results of the present study indicate that the short-term oral intake of l-arginine supplement decreased the resting levels of the insulin hormone and increased insulin hormone immediately after exercise. Likewise, growth hormone increased after 60 minutes. In addition, it showed a decrease in cortisol hormone at 30 and 60 minutes and an increase in testosterone hormone (P<0.05). No significant changes were observed in the levels of other variables (P>0.05).
Conclusion: In general, it seems that L-arginine supplementation has beneficial effects on the short-term recovery of endurance swimmers.