Effects of Exercise Training and Ketone Ester on Muscle Strength and Cardiovascular Response in Parkinson's Disease

Inclusion Criteria: * Diagnosis of Parkinson's Disease Exclusion Criteria: * Any recent changes in EKG, history of myocardial infarction or other cardiac event or other cardiac contraindications to exercise * Inability to use a step, stand, walk, or use a stationary cycle ergometer * History of symptoms in exercise that preclude safe and comfortable participation, such as dizziness and lightheadedness, orthostasis, severe symptomatic leg or back musculoskeletal pain, painful neuropathy, significant ankle edema or medication side effects * History of symptomatic cardiovascular or pulmonary disease interfering with exercise * History of active rheumatoid arthritis * History of uncontrolled chronic pain syndrome * Any other history of medical or psychiatric comorbidity precluding safe participation in the project * Poorly controlled diabetes * Pregnancy or breastfeeding * Clinically significant dementia * Any contraindications to MRI (metal implants, severe claustrophobia, inability to lie still for 1 hour, etc.)