Seven week old male normotensive Wistar-Kyoto (WK) and spontaneously hypertensive (SHR) rats were randomly assigned either to the sedentary group (SHRsed; n=10 and WKsed; n=10) or to the exercise group (SHRex; n=10 and WKex; n=10). Exercise groups were subjected to moderate-intensity exercise on a motor-driven treadmill continuously for a period of 16 weeks. Animals were euthanized twenty-four hours after the last exercise session at the age of 23 weeks and left ventricle (LV) tissues were collected for later analyses. We performed the following experimental procedures: blood pressure measurements, echocardiographic analysis, real time RT-PCR, western blot analysis, electron paramagnetic resonance (EPR) studies, antioxidant assays, electrophoretic mobility shift assay (EMSA), reverse-phase high-performance liquid chromatography (HPLC), ELISA, and statistical analysis.