The Effect of an Acute Swim Exercise Training Session on Changes in Se-rum Beta-endorphin and

Most previous studies were concentrated on plasma beta-endorphin (ß-EP) and cortisol responses following sub-maximal or maximal exercise; however, little researches have been conducted on the efficacy of sports specialized exercise sessions in ß-EP and cortisol secretions. The aim of this study was to assess changes in plasma beta-endorphin and cortisol levels in male sprint swimmers after one session of swim exercise training. 15 healthy male elite swimmers as purposefully and voluntarily participated in an semi-experimental study. After a practice session for 2 hours long swimming, participants were swimming in a 50 meters standard pool with an intensity equivalent to 80-85 percent of maximal oxygen consumption. Venous blood samples were taken from the right arm of the subjects to measure levels of beta-endorphin and cortisol in the three steps: 1. Basic conditions, 2. Immediately after specialized training, and 3. 30 minutes after exercise. Serum blood samples separated immediately in refrigeratored centrifuge in +4 °C and then were transferred to assess the variables to the refrigerator -70 °C. Beta-endorphin and cortisol were measured by ELISA kit. Data were analyzed using repeated measures ANOVA test. There are significant differences between levels of beta-endorphins of male sprint swimmers in the three periods of time before, immediately after and 30 minutes after exercise (P < 0.05). The paired comparison test showed a significant difference between the mean beta-endorphin before and recovery period in the swimmers (P < 0.05). Also, results showed that the changes of cortisol levels in three steps were not significantly different. The results showed that an acute exercise session increase only serum beta-endorphins hormones in sprint swimmers.