Third, nutritional state: High-sugar/high-fat diets (common in T2DM) increase mitochondrial O2•- leakage and reduce glutathione (GSH)—a key scavenger of •OH, whereas exercise-induced GPX1 upregulation (162.4% post-moderate training) restores GSH levels, indirectly limiting •OH-mediated mtDNA oxidation (Brinkmann et al.). This evidence concerns the gene GPX1 and type 2 diabetes mellitus.