Introduction: Due to the use of X-rays in medicine and industry, it seems necessary to study. Research shows that this irradiation can cause oxidative stress and induce destructive effects in kidney. Due to the antioxidant properties of high intensity(HIIT) training, the aim of the present study was effect of high intensity training on serum level of oxidants and antioxidants factors and structural changes on kidney tissue in rats exposed to X-rays. Methodology: In this experimental study 24 male Wistar rats were randomly divided into 3 groups (healthy control, X-ray control and X-ray irradiation with HIIT training). The two under irradiation groups, were exposed to 3Gy X-ray irradiation. The training group also performed high intensity training for 10 weeks. 24 hours after the last training session, blood serum of rats was collected for oxidative and antioxidant factors and kidney tissue was isolated for stereological examination. Data were analyzed by one-way ANOVA and Tukey’s post hoc test at the significance level of P≤0.05. Results: In this study, whole body X-ray irradiation of rats caused a significant increase in kidney volume (P=0.004), cortex volume (P=0.03), interstitial tissue volume (P=0.01), glomerular volume (P=0.03) and serum level of MDA (P=0.001) but on serum level of SOD, medulla volume, proximal tubules volume (total volume, volume of epithelium and lumen), volume of distal tubules (total volume, volume of epithelium and lumen), the length of proximal and distal tubules had no effect. Also, performing high intensity training protocol in rats under X-ray irradiation significantly reduced kidney volume (P=0.03), cortex volume (P=0.04), glomerular volume (P=0.039) and serum level of MDA (P=0.02) but HIIT training did not effect on the serum level of SOD interstitial tissue volume, medulla volume, volume and length of proximal and distal tubules. Discussion: Increase in kidney volume has been observed as one of the first and most important indicators
