Therefore, we prescribed a program of 8‐week treadmill training for type 2 diabetes mellitus (T2DM) rats and determined the role of irisin signaling, via interacting with AMP‐activated protein kinase (AMPK), in mediating the effects of exercise on myocardial injuries and mitochondrial fission. The gene discussed is FNDC5; the disease is type 2 diabetes mellitus.