**Genetics and Aerobic Exercise to Slow Parkinson's Disease Trial** This study explores how exercise and genetics might influence the progression of Parkinson's Disease (PD). Researchers will recruit 200 people with PD from Cleveland and Salt Lake City to join the "Pedaling for Parkinson's" exercise program. Participants will exercise at community centers 3 times a week for a year. They will also undergo genetic testing to see how their genes might affect exercise benefits. Key Points: - **Duration:** The study lasts about 12.5 months, with five in-person visits. - **Visits:** Participants will have check-ups at the Cleveland Clinic or the University of Utah, including a 12-hour medication pause for some assessments. - **Participation Requirements:** Must be able to ride a stationary bike, have reliable transportation, and use a smartphone for activity tracking. This study helps determine if community exercise programs can slow PD and how genetics play a role. Participants will be continuously enrolled and monitored to gather meaningful data. If interested, ensure you meet eligibility criteria and can commit to the study's demands.