The present study shows that acute exercise performed in a cyclergometer by metabolic syndrome patients at 60%–70% of their maximal heart rate for about 30 min does not influence the levels of mitochondrial proteins related with antioxidant (UCP3, MnSOD), respiratory (CoxIV) or mitochondrial remodeling (Mfn1, Mfn2) functions. The gene discussed is UCP3; the disease is metabolic syndrome.