Cognitive Effects of Exercise in Parkinson's Disease

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)