The Effects of An Acute Running Exercise Training Session on Changes in Serum Beta-Endorphin and Cortisol Levels among Male Sprint Runners

Previous studies have often focused on plasma beta-endorphin (ß-EP) and cortisol responses to either sub-maximal or maximal exercise. However, little research has been conducted on the effects of professional exercise sessions on ß-EP and cortisol secretion levels. The aim of this study was to assess changes in plasma ß-EP and cortisol levels in male sprint runners after one session of 200 meters run exercise training. In a quasi-experimental study, 14 healthy male elite runners (mean age: 21.38 ± 2.76 years, mean weight: 69.78 ± 6.76 kg, mean height: 182.21 ± 5.22 cm, and mean body mass index of 20.99 ± 1.62 kg/m2) purposefully and voluntarily participated in this study. After a two hour exercise session, the subjects ran 200 meters in 23 seconds with an intensity equivalent to 80-85% of maximum oxygen consumption. Venous blood samples were taken from the right arm of the subjects to measure levels of ß-EP and cortisol before exercise, immediately after specialized training, and 30 minutes after exercise. Serum blood samples were separated immediately in a refrigerated centrifuge at +4°C. They were then transferred to a -70°C refrigerator for future assessments. ß-EP and cortisol were measured using enzyme-linked immunosorbent assay (ELISA) method. Data was analyzed using analysis of variance (ANOVA). Levels of ß-EP among male sprint runners significantly differed between the three measurements (P ≤ 0.05). The paired comparison test showed a significant difference between the mean ß-EP level before training and in the recovery period (P ≤ 0.05). In addition, no significant differences in cortisol levels were observed (P ≥ 0.05). The results showed that an acute exercise session caused significant increases only in levels of serum ß-EP hormones among sprint runners.