This is a prospective, pre-post intervention study to evaluate the effect of a high-intensity, aerobic exercise program on outcomes of cognition, mood, gait, balance, cardiorespiratory fitness, neuromuscular performance, fatigue, sleep, and quality of life for patients diagnosed with idiopathic Parkinson disease. The primary outcomes will be a composite measure of cognitive function and the Timed Up and Go (TUG).

All subjects will be assigned to aerobic exercise that will use a blend of both unsupervised moderate and supervised high intensity exercise. The exercise will consist of walking / jogging modalities, dependent on the individual's level of bradykinesia and will be paced by the individual's level of perceived exertion. The exercise protocol will be designed to target an accumulation of at least 150 minutes of cardiovascular exercise per week.

Exercise training will be performed 5x/week for a total of 16 weeks. The training will consist of 3 supervised high intensity sessions and 2 at home moderate intensity exercise sessions. The high intensity sessions will be performed on a treadmill at an intensity rating of ~ 15 and 17 on a rating of perceived exertion (RPE) scale of 6 to 20. The moderate intensity exercise will target an RPE of ~10 - 12 and participants will be asked to complete this on their own.

Inclusion Criteria:

• Subjects with idiopathic Parkinson Disease as determined by United Kingdom Brain Bank Criteria. This includes the presence of bradykinesia with one or both of the following: rest tremor and/or rigidity
• Asymmetric onset of PD and progressive motor symptoms.
• Hoehn and Yahr stage 2 or 3.
• Stable dopaminergic medication regimen for 4 weeks prior to baseline visit with no anticipated changes for the duration of the study.
• Stable doses of medications known to affect sleep and medications for Parkinson's Disease for at least 4 weeks prior to study entry without anticipation of medication change for the duration of the study.
• Ability to complete exercise intervention and assessment visits during at least 16 weeks of intervention (3x/week for 16 weeks).
• Must pass a physical examination to assess exercise readiness.
• Women of childbearing potential may enroll but must use a reliable measure of contraception and have a negative serum pregnancy test at the screening visit.
• Montreal Cognitive Assessment score ≥ 18 and ≤30.
• Ability to pass a Physical Activity Readiness Questionnaire to assess exercise readiness.

Exclusion Criteria:

• Atypical features indicative of a Parkinson's Plus disorder (Progressive Supranuclear Palsy, Multiple Systems Atrophy, Corticobasal Degeneration) including cerebellar signs, supranuclear gaze palsy, apraxia, prominent autonomic failure, or other cortical signs.
• Neuroleptic treatment at time of onset of Parkinsonism
• Active treatment with a neuroleptic at time of study entry. Exceptions to this are quetiapine and clozapine.
• History of multiple strokes with stepwise progression of Parkinsonism
• History of multiple head injuries
• Inability to walk without assistance, including a cane, wheelchair, or walker
• Regular participation in an exercise program within the past 6 months.
• Deep Brain Stimulation or other neurosurgical procedure for PD.
• Untreated sleep apnea
• Known narcolepsy
• Participation in drug studies or the use of investigational drugs within 30 days prior to screening
• Acute illness or active, confounding medical, neurological, or musculoskeletal conditions that, at the discretion of the PI, would prevent the subject's ability to participate in the study
• Known contraindication to testing
• Active alcoholism or other drug addiction
• Pregnancy
• Moderate to severe dementia

If data is shared, Investigators plan to obtain a material transfer agreement.