The BEAM study design. The primary aims of this randomized controlled trial are to evaluate the efficacy, safety and feasibility of a 12-week tai chi exercise program as compared to a time- and attention-matched education control. At 12 weeks, subjects in tai chi undergo a second randomization to either continue with tai chi for an additional 12 weeks (total 24 weeks), or to receive usual care. (Exploratory Aim 1: Tai Chi Dosage). To explore the impact of a simplified seated mind-body breathing intervention, a third randomly assigned group receives a 12-week mind-body breathing program (Exploratory Aim 2). After the initial 12 weeks of both education and mind-body breathing, subjects receive usual care for the following 12 weeks. All participants undergo testing at baseline, 12 weeks, and 24 weeks.