Background: Diabetes is a major global disease with a high mortality rate.The impact of exercise on bone tissue protection in diabetic rats during circadian cycle phases is unknown. This study examined the effects of endurance training on genes in diabetic rats during light and dark circadian rhythm phases. The aim of the study:The present study investigated the impact of endurance training on insulin resistance and gene expression in diabetic rats during circadian rhythm phases. Materials and methods: In this study, 18 NMRI mice were randomly assigned to 6 groups: healthy control in the dark, healthy control in the light, diabetic control in the dark, diabetic control in the light, and diabetic exercise in the dark. Then, they developed diabetes after being being fed a high-fat diet and receiving a single injection of streptozotocin. The 8-week endurance training program consisted of 5 days per week of Vmax 50–60%. Blood and bone tissue were removed following anesthesia. Bone tissue was examined for the expression of OPN and OPG genes, Bmal1 protein expression, and insulin resistance index. Results: In diabetic rats, eight weeks of endurance training significantly reduced insulin resistance (P=0.005) and significantly increased the expression of the Bmal1 protein (P=0.009). OPG and OPN variables did not significantly differ between the diabetic and control exercise groups during the changes in the two phases of darkness and light (P>0.05). Conclusion: Endurance training may improve insulin sensitivity in diabetics by enhancing antioxidant system performance and controlling circadian activity. Further research is needed to determine the effects on genes in bone