Age

18–any

Sex

ALL

Healthy volunteers

Not accepted

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

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