BACKGROUND AND PURPOSE In order to explore the possible effects of physical therapy interventions on people with hypertension, we evaluated the effects of aerobic exercise training on myocardial energy metabolism in an animal model of hypertension. SUBJECTS We used 36 female spontaneously hypertensive rats (rats with genetically induced hypertension) and 12 normotensive Wistar-Kyoto rats. METHODS The normotensive rats were sedentary and formed the CONsed group. The spontaneously hypertensive rats were randomly divided into 3 experimental groups (12 rats per group). Hypertensive rats that were sedentary formed the HTNsed group, those that received 8 weeks of exercise training formed the HTNx8 group, and those that received 16 weeks of exercise training formed the HTNx16 group. We measured systolic blood pressure, heart wet weight, maximal activities of cardiac energy metabolism enzymes, glucose transporter content, and total concentrations of protein, glycogen, and triglyceride. RESULTS Systolic blood pressure was greater than 200 mm Hg in the CONsed group at the time of testing. Exercise training modestly (approximately 11-18 mm Hg) lowered blood pressure in the HTNx8 and HTNx16 groups. Fatty acid enzyme activity was greater in the CONsed group than in HTNsed and HTNx8 groups, but activity was roughly equivalent between the CONsed group and the HTNx16 group. Glucose enzyme activity was greater in the HTNx16 group than in the CONsed group and HTNsed group. Intracellular glycogen concentration was greater in the HTNx8 group than in HTNsed group. CONCLUSION AND DISCUSSION Results of this study suggest that aerobic exercises may help to normalize cardiac energy metabolism in mammals with hypertension.