The purpose of this study is to examine the impact of exercise on sleep and cognition in Parkinson’s Disease.

Inclusion criteria, Parkinson’s Disease (PD) group: 45 years of age or older, Diagnosis of Parkinson’s, no contraindications to exercise. Exclusion criteria, PD group: Regular participation in an exercise program, and signs indicative of atypical Parkinsonism. Inclusion criteria, non-PD controls: 45 years of age or older, and on stable medications for at least 4 weeks prior to study entry. Exclusion criteria, non-PD controls: Significant neurological disease, contraindication to MRI, and untreated sleep apnea. Inclusion criteria, study partner: 18 years of age or older and spends at least 10 or more hours per week with the PD subject. Exclusion criteria, study partner: Minor