Participants assigned to this group have been randomized to the Combined group of the parent study, Combining Exercise and Cognitive Training to Improve Everyday Function(EXACT)(Unique Protocol ID 201102416). Participants perform a 6-month standardized aerobic training program at a local recreational center, 3 times per week for 1 hour. Participants in this group also perform an 8-week cognitive training program 3 days per week for 1 hour, during months 5 and 6. The cognitive training program is computer-based, and focuses on 3 types of cognitive processes: task coordination, prospective memory, and retrospective memory retrieval. The cognitive training is conducted on concurrent days with aerobic exercise training sessions, also on site at the recreational center.

Participants assigned to this group have been randomized to the Control group of the parent study, Combining Exercise and Cognitive Training to Improve Everyday Function(EXACT)(Unique Protocol ID 201102416). Participants perform a 6-month home exercise program consisting of stretching, range of motion, and simple yoga exercises designed to improve flexibility. They are instructed to perform these exercises at home at least 3 times per week for 30 - 45 minutes and record their activity on a calendar. Participants also attend weekly 1-hour Health Education sessions for 8 weeks, during months 5 and 6. These sessions cover topics unrelated to exercise or cognition, such as nutrition, hearing loss, stroke, and home energy conservation.

All participants complete MRI scans at baseline and at the end of month 6. Scanning sessions last approximately 30 minutes each and consist of two components: (1) High resolution T1-weighted MPRAGE anatomic images to provide detailed anatomy and maximum gray-white matter contrast for images and to allow any estimate of regional or whole-brain volume, and (2) Resting BOLD functional images to allow assessment of the functional connectivity in large scale networks.