The Entorhinal Cortex and Aerobic Exercise in Aging

The investigators are examining the effects of exercise and cardiovascular fitness on cognitive processes. Specifically, the investigators are examining if exercise improves brain function in a brain area known as the entorhinal cortex. Together with the hippocampus this brain area is important for memory formation and spatial navigation. Participation in this research study will take approximately 4 months. During this time, participants will make three initial study visits. The first visit is for informed consent and screening, the second visit is for baseline fitness testing, and the third visit is for cognitive testing and a functional MRI exam. Functional MRI is a brain imaging technique that uses a magnetic field to "take pictures" of the brain while a person performs a cognitive task. It will take up to approximately three weeks to complete these initial three study visits. Following the three initial study visits, the exercise-training program will begin. Participants will be randomized to one of two training programs: a cardiovascular endurance-training program (aerobic exercise) and a strength, balance, and flexibility training program (non-aerobic exercise). The exercise training program will last 12 weeks. There will be three one-hour exercise sessions per week. After completion of the exercise-training program, participants will attend two follow-up study visits. The first follow-up visit is for fitness testing. The second follow-up visit is for cognitive testing and an MRI exam.