Hyperbaric oxygen therapy, breathing pure oxygen in a pressurized chamber over dozens of sessions, is a medical procedure also sold for longevity. Best-supported uses are some non-healing diabetic wounds, radiation-damaged tissue and sudden hearing loss, though several careful trials found no benefit. Thinking, fitness and cellular-aging claims rest on early, short-term evidence, mostly from one commercially tied center. Harms are usually mild, serious ones rare; cost and time are high. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Pre-session capillary glucose (diabetes) | Above 120 mg/dL before each session | Safety: prevents hypoglycemia |
| HbA1c | Below 8% for trial eligibility | Safety: uncontrolled diabetes excluded |
| Refraction and visual acuity | No established target; track change from own baseline | Safety: detects myopic shift and cataract |
| Eardrum appearance (otoscopy) | No established target; track Teed grade change from baseline | Safety: barotrauma pauses or changes sessions |
| Spirometry (FEV1, FVC) | FEV1, FVC and FEV1/FVC at or above the lower limit of normal for age, sex and height | Safety: lung disease or oxygen toxicity |
| Left-ventricular ejection fraction | 52–72% in men, 54–74% in women | Safety: low values flag pulmonary-edema risk |
| VO₂max (cardiopulmonary exercise test) | No established target; track change from own baseline | Expected to change: aerobic capacity |
| Global cognitive score (computerized battery) | No established target; track change from own baseline | Expected to change: cognition |
| Pittsburgh Sleep Quality Index | 5 or lower | Expected to change: sleep quality |
Cadence: Baseline testing before starting; ear checks after the first three sessions and whenever pain occurs; glucose before and after every session in diabetes; refraction at course end (about 12 weeks) and a lens examination if sessions exceed 150; repeat cognitive, sleep and exercise testing at course end and again 3–6 months later