IHT for Mild Cognitive Impairment

Inclusion Criteria: * Adult men and women ages 55 to 79 years old who have been diagnosed with MCI. * Must be willing to be assigned to either group: treatment or sham-treatment control. * Able to pay multiple visits to the lab for the proposed assessments. * Able to breathe moderately hypoxic air via an air-cushioned, disposable facemask. * To have controlled stabilized chronic conditions of at least 6 months duration, such as hypertension, coronary artery disease, diabetes or metabolic disease, chronic bronchitis, degenerative osteoporosis or arthritis and/or other aging-related chronic conditions. * Must be depression-free at the time of enrollment. * Must have arterial oxygen saturation at or above 95% and cerebral tissue oxygenation at or above 50% at rest. * Woman subject must be post-menopausal. Exclusion Criteria: * Unwilling to sign a written consent to participate in this double-blinded placebo-controlled phase I trial. * Diagnosed with AD-dementia or have impaired independent daily functioning; with MMSE \<20 and/or CDR ≥1. * Unable to visit the lab independently. * Claustrophobic to facemask and hyper-reactive to hypoxia exposure. * Expecting any major surgery or transplant. * Have un-controlled chronic conditions including systolic-diastolic pressures over 150/90 mmHg with medications, diabetes, chronic renal failure (based on the medical history questionnaire), obstructive sleep apnea (based on the medical history), recurrent chest pain, seizures or epilepsies, moderate to severe carotid stenosis or calcification, brain aneurysm, uncontrolled allergic rhinitis, pulmonary fibrosis, emphysema, cancer, infectious disease, atrial fibrillation, regular pre-mature ventricular contractions, myocardial ischemia or infarct, 2nd or 3rd degree atrio-ventricular blockade. * Have severe head injury or traumatic brain injury, stroke (hemorrhagic and/or ischemic). * Have currently diagnosed depression. * Currently have COVID-19. * Have any metallic implants or who are claustrophobic. * Currently participating in any interventional study and/or have been previously exposed to hypoxia, such as residing more than two months at altitudes above 5000 ft. within the past 3 years or previously participated in a hypoxia training study.