High Intensity Interval Training Is More Beneficial to Regulate Free Radicals and mtDNA Oxidative Damage in Aged Rats.

Background: The aim of this study was to compare the effect of 12 weeks of high intensity interval training (HIIT) and continues training (CT) on SIRT3 protein level, FOXO3 gene expression, and mtDNA oxidative damage in gastrocnemius of female aged rats. Methods and Results: Female wistar rats (18 months, 250-300 g, n=36) were divided into three groups (HIIT, CT, control). Based on aerobic capacity determined using the ramp protocol, HIIT intensity corresponded to 85-90% and CT was 65-70% of VO2max. Rats trained three times per week for 12 weeks. Forty-eight hours after the last training session, rats were sacrificed and gastrocnemius muscle excised. Our results showed that both exercise protocol increased SIRT3 protein content and FOXO3 gene expression compared to control. However, no significant difference was observed between HIIT and CT. In addition, our data showed that MnSOD activity was significantly higher in HIIT compared to both CT and control and CT versus control. Finally, the level of 8-OHdg was significantly lower in HIIT and CT compered to control and there was no significant difference between HIIT and CT. Conclusion: Our results showed that 12 weeks of HIIT and CT increase SIRT3 protein content, improve antioxidant defense of aged female waster rats. Therfore, HIIT is a time efficient protocol for improving some aspects of mitochondrial function.