Moderate Versus High Volume Light-Moderate Intensity Exercise for People With Moderate Parkinson's Disease

Inclusion Criteria: Participants recruited for this study will be age 40 and older with diagnosis of "definite" PD based upon established criteria (Hughes, Daniel et al. 1992) and determined by a board-certified neurologist with specialty training in movement disorders. Individuals must have presented with asymmetric symptoms that included at least 3 of the cardinal signs of PD (rigidity, bradykinesia, tremor, postural instability), and must show clear symptomatic benefit (e.g., alleviated rigidity, bradykinesia, and tremor) from antiparkinsonian medications, e.g., levodopa (Kempster, Williams et al. 2007). They should be in H\&Y stages 2, 2.5 and 3, and receive a Montreal Cognitive Assessment (MoCA) score \>17 (Litvan, Goldman et al. 2012). Age 40 is the upper limit for young onset PD. We will not recruit individuals with a history of significant alcohol or drug use, nor habitual users of antipsychotics. We will observe patients while OFF their antiparkinsonian medications to avoid dyskinesia, and medication fluctuations that may impact neurophysiology and motor examination. We have successfully observed patients while OFF in several previous trials. The following inclusion criteria apply: * MoCA score \>17 * Able to walk with or without an assistive device at least 10 feet * Best corrected/aided acuity better than 20/70 in the better eye * Willingness to be randomized to a treatment group * H\&Y stages 2, 2.5 and 3 * Show clear symptomatic benefit (e.g., alleviated rigidi…