Background and Objective: Aging is associated with increased free radical production. On the other hand, sports activities with the improvement of antioxidant system can reduce the damage caused by aging. This study was performed to determine the effect of the coantinus training (MCT) and high intensity interval training (HIIT) on antioxidant enzymes in the heart of old rats.

Methods: This experimental study was performed on 24 male Wistar rats aged 22-24 months. After two weeks of adaptation, animals were allocated into three groups including HIIT (8 rats: 100-80% maximum speed), MCT (8 rats: 65-70% maximum speed) and control group (8 rats the control group did not receive any intervention during the study. The training protocol was performed 5 days in week for 6 weeks. The heart tissues of rats were extracted 48 hours after the last training session. Gene Expression of superoxide dismutase (SOD) and glutathione peroxidase (GPX) was analyzed by the ELISA test.

Results: SOD was significantly increase in MCT (41.26±3) and HIIT (48.8±6) groups in compare to control (22.62±2) (P<0.05). GPX was significantly increased in MCT (1.96±0.07) and HIIT (2.28±0.03) groups in comparision with controls (1.37±0.04) (P<0.05) and this increase was higher in the HIIT group than in continuous training group.

Conclusion: Continues training and high intensity interval training increase the amount of antioxidant enzymes in heart tissue of aging rats.