Background & Objectives: Numerous studies have been conducted to assess the effects of acute resistance exercises on the structure and the function of heart, but little works done on effects of chronic resistance exercises. So, the objective of current study was to investigate the long term effect of regular exercises on cardiac function and oxidative stress.

  Methods: Forty male Wistar rats in the weight range of 250- 300 g were used in this study. They were divided in 2 following groups: The 3 months exercises test group and control group which remained without exercises. Regular resistive exercise was carried out according to the model proposed by Tamaki et al. Test group rats exercised for three months. Finally the hearts of 10 rats in each group were taken for homogenization, oxidative stress measurement and the other ten were examined for heart function. Malondialdhyde as an index of oxidative stress and superoxide dismutase, glutathione peroxides and catalase as an indicator of antioxidant capacity with special kits were specifically measured.

  Results: Regular resistive exercise didn't significantly affect the rats' weight, but heart weight in exercise group showed a significant increase (p<0.05). There was a significant decrease in heart rate in exercise group (p<0.05). Left ventricle contraction strength and coronary flow had a significant increase in exercise group in comparison with control group (p<0.05). There was not any significant difference in Malondialdhyde and antioxidant enzymes activity.

  Conclusion: This study showed that, heart efficiency had a significant improvement under effect of regular resistive exercise. Meanwhile, regular resistive exercise didn’t have any significant effect on oxidative stress and heart antioxidant defense capacity.