Yet unlike sedentary individuals with comorbid depression and Type-2 diabetes, endurance-trained athletes appear to exhibit a higher mitochondrial density and mitochondrial enzyme capacity, which enhances oxidative phosphorylation and reduces the degree of insulin-sensitizing metabolic byproducts (Attie and Kendziorski, 2003; Mootha et al., 2003; Patti et al., 2003; Tarnopolsky et al., 2007). Here, INS is linked to type 2 diabetes mellitus.