Overview
2.0 ATA is the pressure used in the majority of Efrati-lab neurological HBOT trials — including the landmark TBI, stroke, and fibromyalgia studies. At this depth a patient breathing 100% oxygen reaches arterial oxygen tensions above 1,000 mmHg, driving angiogenesis, mitochondrial recovery, and neuroplasticity. It is well-tolerated with low barotrauma risk and short compression/decompression windows.
2.0 ATA has emerged as the pressure of choice for research-stage neurological HBOT. The Efrati Lab in Tel Aviv has built the strongest neurological HBOT evidence base at exactly this pressure, with trials across TBI, stroke, long COVID, fibromyalgia, and age-related cognitive decline. The consistency of positive results at 2.0 ATA — contrasted with mixed results at 1.5 ATA — has driven clinical practice.
Pharmacologically, 2.0 ATA with 100% oxygen elevates arterial oxygen tension (PaO₂) above 1,000 mmHg — a 10-fold increase over normal breathing at sea level. The dissolved-plasma oxygen is sufficient to reach hypoperfused brain tissue by diffusion, bypassing compromised vascular supply. HIF-1α stabilisation drives downstream angiogenesis, and neuroplasticity signalling is upregulated.
2.0 ATA sessions are 90 minutes with scheduled 5-minute air breaks every 20–30 minutes to minimise CNS oxygen toxicity risk. The standard neurological course delivers 40 sessions over 8 weeks (five days per week). Response typically develops progressively through the course and continues to accumulate for 1–3 months post-treatment during the delayed neuroplasticity window.
2.0 ATA is also used in wound care at the lower end of the UHMS clinical range, in paediatric protocols, and in some veterinary HBOT. Barotrauma risk is low; CNS oxygen toxicity seizures are rare (~1 in 10,000 sessions) with proper air-break protocols.
How It Works
Chamber pressurised to 2.0 ATA (approximately 14.7 psi above atmospheric). Hard-shell monoplace chambers deliver 100% medical-grade oxygen directly; multiplace chambers pressurise with air and deliver oxygen via hood or mask. Compression over 10–15 minutes; 60 minutes at depth on oxygen with scheduled 5-minute air breaks every 20 minutes; 10–15 minute decompression. Total session approximately 90 minutes.
Protocol Parameters
| Pressure | 2.0 ATA (≈ 14.7 psi above atmospheric) |
|---|---|
| Session length | 90 minutes (60 min on O₂ + 2 × 5-min air breaks) |
| Frequency | 5 sessions/week |
| Typical course | 40–60 sessions |
Indications
- Traumatic brain injury
- Stroke recovery
- Long COVID
- Fibromyalgia
- Post-concussion syndrome
- Chronic wound healing (lower-end protocols)
- Age-related cognitive decline (research)
The 2.0 ATA pressure is the research gold-standard for neurological HBOT. For UHMS-approved wound-care indications, 2.4 ATA is more commonly used, but 2.0 ATA appears clinically acceptable with similar protocols. Emergency indications require higher pressures.
Evidence Base
Strongest evidence base of any HBOT pressure. Hadanny & Efrati publications, Boussi-Gross stroke RCT (2013), Zilberman-Itskovich long COVID RCT (2022), Efrati fibromyalgia trial (2015), Hachmo longevity biomarker trial (2020).
The 2.0 ATA pressure sits at the methodological core of modern neurological HBOT research. Nearly every major Efrati Lab trial uses this pressure. The consistency of positive results across neurological indications supports 2.0 ATA as the research-standard pressure for brain-focused HBOT.
Cautions & Notes
- Still off-label for most neurological indications in the US
- Requires 100% O₂ via hood/mask in multiplace or sealed monoplace environment
- Scheduled air breaks required for CNS oxygen toxicity prevention
- Full course requires 8-week daily attendance commitment
Practical Considerations
2.0 ATA is the research-aligned pressure for neurological protocols. Many clinical facilities offer this pressure for off-label indications. Course duration is substantial (40 sessions × 8 weeks). Response typically continues to improve for 1–3 months post-course.
Frequently Asked Questions
Why is 2.0 ATA the research-standard pressure?
The Efrati Lab in Tel Aviv has consistently published positive neurological HBOT results at 2.0 ATA across TBI, stroke, long COVID, fibromyalgia, and other indications. The pressure appears to represent an optimal balance of therapeutic oxygen delivery and tolerability.
Is 2.0 ATA FDA-approved?
FDA-cleared chambers can operate at 2.0 ATA. Specific indications are approved separately. UHMS-approved indications generally use 2.4 ATA; most 2.0 ATA use for neurological indications is off-label.
How long is a course at 2.0 ATA?
The research-standard protocol is 40 sessions over 8 weeks (five days per week). Some protocols extend to 60 sessions. Response often continues to improve for 1–3 months post-course.
Research disclaimer: This protocol summary is for educational purposes only. HBOT is a regulated medical treatment that must be administered under appropriate professional supervision. Always consult a qualified physician before initiating hyperbaric therapy.