As such, the purpose of the present study is to determine the effects of chronic HIIT (4 times per week for 8 weeks) on the mRNA expression of several key RAAS-related genes (Ren, Agt, Ace, Agtr1a, Agtr1b, and Cyp11b2), as well as traditional clinical markers of CKD (creatinine, albumin, total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides, blood pressure, body weight, kidney weight, and kidney weight-body weight ratio), in an animal model of early-stage CKD. Here, REN is linked to chronic kidney disease.