This pilot study will evaluate the short-term (3 months) and long-term (6 months) effectiveness of a high-intensity interval training (HIIT) program in improving cognitive function and self-efficacy in individuals with PD.

Participants will be assigned to either the HIIT group, which will engage in 3 classes per week, or a standard-of-care control group, which will include people who will continue their standard care and usual physical activities but do not plan on partaking in additional structured exercise interventions for 3 months (except for physical and occupational therapy if medically necessary). Cognitive functions will be measured using standardized tests (Stroop, Trail Making Test-B (TMT-B), verbal fluency (using letters F-A-S), and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)), alongside assessing subjective ratings of daily cognitive function using the Neuro Quality of Life - Cognitive Function (Neuro-QoL CF) survey. Secondary outcomes will include self-efficacy measures, specifically regarding goal achievement, managing emotions and daily activities. We will also aim to obtain brain functional MRI (fMRI) and neuromelanin-sensitive MRI (NM-MRI) data from a subset of participants to measure the brain effects of HIIT as exploratory outcomes.

Inclusion Criteria:

• Diagnosis of idiopathic Parkinson's disease
• Age 40 year and above
• Willingness and ability to participate in HIIT exercise classes

Exclusion Criteria:

• Non-English speaking
• Neuropsychiatric disorder other than Parkinson's disease and comorbid depression and anxiety (e.g., stroke, epilepsy, brain tumor, multiple sclerosis, schizophrenia, bipolar disorder, obsessive compulsive disorder, etc.)
• High levels of exercise at baseline (exercising at high intensity at least 3 times per week or moderate intensity at least 5 times per week)
• Hoehn & Yahr disease stage > 3 (physically not independent)

This is an early-phase pilot study to determine feasibility.