Non-invasive Treatment for Long COVID (Post COVID-19 Condition) Brain Fog

Inclusion criteria: * English speaking * Diagnosis of Long COVID Exclusion criteria: * Any history of: * Coronary artery dissection or aortic dissection * Neurological disease (e.g. dementia, Alzheimer's disease, or other brain-related disease) * Cerebrovascular disease or stroke * Aneurysm * If currently has: * Moderate-severe chronic obstructive pulmonary disease * Uncontrolled moderate-severe asthma * Moderate-severe bronchiectasis * Moderate-severe interstitial lung disease, requiring the use of supplemental oxygen * A necessity to use supplemental oxygen, for any reason * New or worsening symptoms (decompensation) of heart failure * Right heart disease due to chronic pulmonary disease/sleep apnea * Uncontrolled myocardial ischemia or angina * Uncontrolled heart arrhythmias * Heart or lung infection (e.g. myocarditis or pericarditis) * Left main coronary artery stenosis * Moderate-severe aortic stenosis * Pulmonary embolism, pulmonary infarction, or other blood clots * Severe respiratory disease * Chronic kidney disease * Chronic liver disease * Females of childbearing potential will complete a urine pregnancy test at their baseline visit to rule out pregnancy * BMI \>40 * Study staff unable to obtain adequate signal for cerebral blood flow