Cross-System Effects of Acute Intermittent Hypercapnia-Based Interventions in PD

Inclusion Criteria: 1. adults 40 to 75 years of age (the latter to reduce the likelihood of cardiovascular disease) 2. diagnosis of idiopathic Parkinsonism with Hoehn and Yahr stages 2-4 3. medically stable with physician clearance 4. ability to ambulate at least 10 feet with/without assistance 5. ability to follow directions 6. willing to abstain from blood donation for the duration of the study Exclusion Criteria: 1. additional neurologic conditions 2. severe illness or infection, including respiratory/cardiovascular/lung disease, or uncontrolled hypertension 3. inspiratory stridor 4. pregnancy due to unknown tAIH effects on a fetus, although females of childbearing age will not be excluded\* 5. cigarette smoking or vaping within 5 years 6. history of head/neck/lung cancer with the exception of basal cell carcinoma 7. is currently participating in another research study that could influence the results from this study 8. has deep brain stimulation electrodes implanted or has a history of deep brain stimulation 9. faints or becomes lightheaded at the sight of blood * If a female of childbearing potential indicates there is a chance she could be pregnant, she will be provided a pregnancy test and allowed to continue in the study if negative. This is because the fetal risks associated with intermittent hypoxia are unknown.