Blood Flow Restriction and Exercise in Parkinson's Disease

The goal of this clinical trial is to learn whether training with blood flow restriction (BFR), combined with aerobic exercise (performing stepping on a Nu-Step exercise machine), can help improve mobility and other outcomes in people with progressed Parkinson's disease. The investigators hypothesize that training with BFR and aerobic exercise will produce enhanced outcomes related to mobility and quality of life. BFR uses inflatable cuffs placed on participants' upper legs to gently reduce blood flow to the legs while exercising. This has been shown in studies in older adults and Parkinson's disease to improve strength while training with lighter loads, which may be helpful for people with Parkinson's. Participants will be asked to complete 2 weekly training sessions (approximately 30 minutes each) for 8 weeks consisting of supervised aerobic stepping exercise on a Nu-step machine with BFR application during timed intervals. In addition to the training sessions, participants will be asked to periodically perform confidential surveys and tests related to function and disease symptoms, and wear a provided smartwatch (which can be kept upon successful completion of the study). All sessions involve individual monitoring and medical supervision by licensed physical therapists as well as access to all necessary equipment.

Inclusion Criteria: 1. Age 18+ 2. People with advanced Parkinson's disease. "Advanced PD" will include signs of progressed disease including orthostatic hypotension and/or motor issues reflective of postural instability and/or mild-moderate bilateral symptoms (confirmed visually in clinic or home by a medical provider such as an MD/PT and/or documented in the medical record. 3. Ability of individual or legal guardian/representative to understand a written informed consent document, and the willingness to sign it. 4. Diagnosis of idiopathic Parkinson's disease (self-reported okay, documented preferred) 5. Independent ambulation (≥10m with or without an assistive device) 6. Commitment to participate in the exercise intervention as outlined 7. Score of ≥21 on the Montreal Cognitive Assessment (MoCA) Exclusion Criteria: 1. History of cardiovascular disease, uncontrolled hypertension (blood pressure ≥140/90 mmHg), deep-vein thrombosis, varicose veins, or rhabdomyolysis which a patient's primary physician determines would preclude them from safe study participation. 2. Ankle branchial index ≤ 0.9 or \> 1.3 3. History of or comorbid conditions spanning cardiovascular, neurological, or orthopedic injuries which may prevent for the safe administration of the intervention (a healthcare provider's clearance or guidance will be obtained in these situations to ensure appropriateness), including current medications. 4. History of uncontrolled diabetes, BMI \> 40, or severe cognitive impairment (as measured by MoCA \