fa آسیب شناسی ورزشی و حرکات اصلاحی Sport injury and corrective exercises پژوهشي Research <p style="text-align: justify;"><strong>Purpose: </strong>This study aimed to investigate the effect of one intensive training session on the changes of beta-endorphin and serum cortisol levels of elite wrestlers.</p> <p style="text-align: justify;"><strong>Methods:</strong> In this quasi-experimental research with one group and pretest-posttest design, 16 elite wrestlers within the age range of 18 to 25 years were purposefully and selected and they voluntarily participated in the research. The subjects performed one session of intensive exercise with the intensity of 85% to 90% of maximum heart rate. The blood samples (5 mL) were collected two times. First it was taken 30 minutes before the exercise and second blood sample was taken immediately after exercise by one expert and two physicians. The data were analyzed by paired-samples t-test using SPSS 17 and &alpha; value was set at 0.05.</p> <p style="text-align: justify;"><strong>Results: </strong>There was a significant difference between beta-endorphin levels of elite wrestlers before and immediately after the exercise session (P=0.024). The serum cortisol level also increased significantly during the test (P=0.048).</p> <p style="text-align: justify;"><strong>Conclusion:</strong> According to the findings of the study, beta-endorphin increase can make happy the athletes. Furthermore, the rise of cortisol level can increase the efficiency of immune system, boost the energy, maintain the body balance, and decrease the pain sensation.</p> <p></p> Beta-endorphin, Serum cortisol, Exercise, Athletes 171 176 http://ptj.uswr.ac.ir/browse.php?a_code=A-10-279-9&slc_lang=fa&sid=1 Mansour Enayatjazi No Department of Sport Physiology, Faculty of Physical Education, University of Isfahan, Isfahan, Iran. Saeed Sadeghi Dinani aemami@ut.ac.ir Yes Department of Sport Physiology, Faculty of Physical Education, University of Isfahan, Isfahan, Iran. Seyed Ali Emami Hashemi No Department of Health and Sport Medicine, Faculty of Physical Education and Sport Science, Kharazmi University, Tehran, Iran.