Study in Parkinson Disease of Exercise

This study is a Phase 3 multi-site, randomized, evaluator-masked, study of endurance treadmill exercise on changes in the Movement Disorder Society-Unified Parkinson Disease Rating Scale (MDS-UPDRS) Part III score at 12 months among persons with early stage Parkinson disease. 370 participants will be randomly assigned to 2 groups: 1)60-65% HRmax or 2)80-85% HRmax 4 times per week. The primary objective is to test whether the progression of the signs of Parkinson's disease is attenuated at 12 months in among persons who have not initiated medication for Parkinson Disease (PD) when they perform high-intensity endurance treadmill exercise.