Hyperbaric oxygen therapy delivers 100% oxygen at 1.5-3.0 atmospheres absolute pressure in a sealed chamber. Saturates plasma with oxygen, bypassing hemoglobin's normal carrying limit.
Mechanism — Drives oxygen into tissues with poor perfusion, stimulates angiogenesis, mobilizes stem cells, induces hormetic stress response. FDA-approved for decompression sickness, carbon monoxide poisoning, certain wound and radiation injuries.
Use case — Off-label longevity and recovery protocols use 1.5-2.0 ATA for 40-60 sessions. Telomere lengthening and senescent cell reduction have been shown in small trials (Efrati et al). Soft-shell chambers (mild HBOT at 1.3 ATA) offer modest benefit at lower cost.
Caveats — Real medical contraindications (untreated pneumothorax, certain ear conditions). Quality of clinic matters enormously. Costs are non-trivial; weigh against more leveraged interventions.