The proposed multi-site, Genetics and Aerobic Exercise to Slow PD (GEARS) Trial will, for the first time, determine the interplay between genetics and exercise in altering PD progression. In sum, 200 PD patients will be recruited from the Cleveland and Salt Lake City metro areas to participate in the Pedaling for Parkinson's (PFP) community-based exercise program. Participants will exercise at community-based sites 3x/week for 12 months. All participants will undergo genotyping using an array that includes the genome backbone and common risk variants associated to increase risk for multiple neurological disorders including PD.