Introduction:Pathway apelin/APJ is one of the positive powerful inotropic substances which is an important regulator of cardiovascular operation and a significant factor in cardiovascular tissue. The aim of the present study is to investigate the effect of eight weeks high intensity interval training (HIIT) and continuous Training on apelin levels of cardiac tissue in healthy male rats. Material & Methods: In this research, 30 Wistar 2-month male rats were chosen with average weight 180 ± 20 gr and randomly divided into 3 groups: continuous training (n=10), HIIT (n=10) or control group (n=10). Continuous training and HIIT groups have been engaged in exercising according training program in five days a week for 8 weeks. For the comparison among the groups, one-way analysis of variance (ANOVA) was performed. Results: No significant differences were observed in apelin levels between continuous training, HIIT and control group (P=0.29). Conclusion: According the results of this study, both exercises increased the apelin levels in heart; however this increase was not significant. It seems that the response of this hormone is different in organs so that it has more limitation in heart tissue than other organs. Therefore, it has been assumed that making noticeable changes in apelin levels of heart required much more time. پرونده مقاله