Holoic Systems · Oxygen therapy information
HBOT Oxygen Information Resource
Hyperbaric oxygen therapy (HBOT) is a medical treatment in which you breathe a high concentration of oxygen inside a pressurised chamber. This resource explains what it is, how it works, what a session involves, what it is cleared to treat, and what to ask your care team.
A 15-second animation. Sound is off until you ask for it. Every element is drawn live in the page — no video files, no external requests.
About the animation: the craft, the dolphin and the singing are fiction — a friendly picture of calm, not a depiction of a real chamber, a real session, or a promise of any clinical or relaxation benefit. Hyperbaric chambers are medical devices operated by trained staff.
What is HBOT?
Ordinary air at sea level is about 21% oxygen at 1 atmosphere absolute (ATA). In hyperbaric oxygen therapy you sit or lie inside a sealed chamber while the pressure is raised — typically to 2.0–3.0 ATA — and you breathe close to 100% oxygen.
The combination matters. Pressure is what makes HBOT different from simply breathing oxygen through a mask at home: at raised pressure, oxygen dissolves directly into the blood plasma, so it can be delivered to tissue even where circulation is poor or a vessel is blocked. That is the mechanism behind nearly every use of the therapy.
Exact pressures, durations and course lengths are set by the treating clinician and vary by condition, protocol and country.
How it works
HBOT is not one trick but several overlapping effects. Which ones matter depends on what is being treated.
Plasma hyperoxygenation
Dissolved oxygen in plasma raises tissue oxygen tension far above what red blood cells alone can carry — reaching tissue that a compromised blood supply would otherwise starve.
New blood-vessel growth
Repeated exposure stimulates angiogenesis: new capillaries grow into poorly perfused, irradiated or chronically wounded tissue.
Wound healing
Fibroblast activity, collagen deposition and new tissue formation are all oxygen-dependent, so healing stalls when tissue oxygen is low.
Immune function
Oxygen-dependent killing by white blood cells improves, and some antibiotics work better in an oxygen-rich environment.
Oedema control
Vasoconstriction without hypoxia reduces swelling in injured, burned or grafted tissue while oxygen delivery is maintained.
Bubbles and toxins
Helps shrink and clear gas bubbles (decompression sickness, arterial gas embolism) and accelerates clearance of carbon monoxide.
What a session is like
- Screening first. A clinician reviews your history, medications and implants before you ever get in. Safety screening is not optional — it is the treatment.
- Change and settle in. You change into facility-provided cotton and take a seat or lie down in the chamber. What you have to leave outside depends on the chamber: an oxygen-pressurised chamber excludes metal, electronics, flammables and cosmetics outright, while a chamber pressurised with compressed air does not enrich its atmosphere and so carries much lighter restrictions.
- Pressurisation. Pressure rises over roughly 10–15 minutes. Your ears feel like they do on a flight — you equalise by swallowing, yawning or gently blowing against a closed nose. Tell staff if you cannot clear your ears; it is common and manageable.
- At treatment pressure. You breathe oxygen through a hood or mask, usually in blocks with short air breaks to reduce oxygen toxicity risk. Most people read, rest or watch something. Some feel mild warmth; some feel nothing much at all.
- Depressurisation. Pressure comes down slowly, again 10–15 minutes. Ears may pop again. Afterwards you may feel tired or hungry — that is common.
- Repeat. Benefit usually comes from a course of sessions over weeks, not a single visit. Your team should define in advance what is being measured and when to stop if it is not working.
Worth knowing: chambers come in two main types — monoplace (one person, a clear tube) and multiplace (several people, with staff inside). Both raise pressure; the choice is clinical and logistical. They also usually differ in what they are pressurised with, which is what drives the fire-risk difference above: a monoplace chamber is commonly pressurised with pure oxygen, while a multiplace chamber is usually pressurised with compressed air and delivers oxygen to each person by mask or hood.
What HBOT is cleared to treat
The list below is a general summary of indications that regulators such as the US FDA have cleared HBOT for. Cleared indications differ between countries and change over time.
Emergency and acute uses
- Decompression sickness
- Arterial gas embolism
- Carbon monoxide poisoning (with or without cyanide)
- Gas gangrene
- Necrotising soft-tissue infections
- Crush injury and compartment syndrome
- Acute traumatic ischaemia
- Severe anaemia when transfusion is not an option
- Thermal burns
- Intracranial abscess
Chronic and adjunctive uses
- Non-healing diabetic foot wounds
- Chronic refractory osteomyelitis
- Delayed radiation injury in bone and soft tissue
- Radiation injury to bladder, bowel or soft tissue
- Compromised skin grafts and flaps
- Idiopathic sudden sensorineural hearing loss
Verify before relying on this list. It is a plain-language summary for orientation only, not a billing or eligibility source. Cleared indications vary by regulator and by jurisdiction, and the evidence for each ranges from very strong to limited. Always confirm the current position with your own clinician and the relevant regulator.
Many other uses — from long COVID to autism to sports recovery to “anti-ageing” — are promoted well beyond the evidence. Some are being studied properly; some are marketed as certainties. A good rule: if someone guarantees a cure and asks you to pay up front, slow down.
Risks, side effects and contraindications
In a properly run facility with proper screening, serious complications are uncommon. They are not zero, and the common ones are genuinely annoying rather than dangerous.
Common side effects
- Ear and sinus barotrauma — the most frequent problem, usually from difficulty equalising
- Temporary short-sightedness (reversible myopia), typically resolving over weeks
- Middle-ear fluid or discomfort after a session
- Claustrophobia, anxiety or restlessness in the chamber
- Tiredness, headache, light-headedness
- Low blood sugar in insulin-dependent diabetes
Uncommon but serious
- Oxygen toxicity — seizures (central nervous system) or lung irritation (pulmonary), which is why air breaks and dose limits exist
- Pneumothorax or air embolism — rare, and the reason for strict screening and protocols
- Aggravated pre-existing lung disease, or cataract progression with repeated long courses
Contraindications and cautions
Usually an absolute no
- Untreated pneumothorax
- Certain chemotherapy agents that increase oxygen toxicity risk (for example doxorubicin and bleomycin) or concurrent disulfiram
- Implanted devices not rated for pressure
Needs a specialist decision
- Blocked nose, sinusitis, cold or an ear you cannot equalise — often simply rescheduled
- Severe COPD with carbon dioxide retention
- Pregnancy
- Uncontrolled fever, seizure history, or significant heart failure
- Implanted pacemaker or defibrillator, cochlear implant, some pain pumps
Fire risk depends on what the chamber is pressurised with. A chamber pressurised with pure oxygen — as many single-person “monoplace” tubes are — carries a real fire risk: in a high-pressure oxygen atmosphere, materials ignite and burn far more readily. A chamber pressurised with compressed ordinary air does not pose that fire risk, because its atmosphere stays at roughly normal oxygen concentration.
In an air-pressurised chamber, oxygen is delivered to your mask or hood for breathing and is vented out of the chamber, so it does not significantly raise the oxygen concentration inside. The chamber's oxygen concentration is monitored continuously and is reduced — by venting — if it rises above about 25%.
That is why the rules differ between facilities. An oxygen-pressurised chamber excludes lighters, electronics, alcohol-based products, oils and synthetic clothing outright, because there they are genuinely dangerous. An air-pressurised chamber may restrict far fewer items. Ask which type of chamber you will be treated in.
Questions to ask your care team
Take these to your appointment. Write the answers down.
- Is my condition one that HBOT is cleared or well evidenced for — and what is the evidence in my case?
- What exactly are we measuring, and when will we decide whether it is working?
- How many sessions, how long each, and how many per day or per week?
- What are the risks for me specifically, given my history and my current medications — including any chemotherapy?
- Could this interact with my drugs, my implants or my diabetes management?
- Is it an adjunct to my existing treatment, or a replacement? (Almost always an adjunct.)
- What does it cost, and is any of it covered?
- Who supervises the chamber, what training do they have, and what safety standards does the facility follow?
Frequently asked questions
Is HBOT the same as breathing oxygen at home?
No. A home oxygen concentrator delivers oxygen at normal pressure, which helps when your blood oxygen is low. HBOT raises the pressure as well, which is what dissolves oxygen into plasma and pushes it into tissue that normal breathing cannot reach. Same gas, different physics.
Does HBOT replace surgery, antibiotics or other treatment?
Almost never. It is used as an adjunct — something added to the main treatment, usually because the tissue is not getting enough oxygen to heal on its own. It does not remove the need for debridement, antibiotics, revascularisation or whatever else your team has planned.
Is it safe?
For most people, in a properly equipped facility, after proper screening: yes, with a low rate of serious complications. The common problems are ear discomfort and temporary vision changes. The serious risks — oxygen toxicity and pressure injuries — are why screening, air breaks, dose limits and trained supervision matter. If a facility cannot answer detailed safety questions, go elsewhere.
Can I buy a chamber?
A soft portable “mild hyperbaric” bag generally reaches only a fraction of the pressure of a medical chamber and is not cleared for the treated indications. It is not a substitute for treatment, and the evidence for the wellness claims made about it is weak.
If you are considering a chamber of your own, we can help you buy a hard-shell 2.0 ATA chamber customised to your needs. A chamber is a medical device, so discuss how you would use it with your clinician before spending money.
Why do I have to take my watch and phone off?
It depends on the chamber. In a chamber pressurised with pure oxygen, the atmosphere itself is oxygen-enriched, so a spark, a lithium battery or an alcohol-based hand sanitiser can be genuinely dangerous, and those items are excluded outright. In a chamber pressurised with compressed air, the atmosphere is ordinary air and is not a fire risk at all: oxygen goes to your mask and is vented out of the chamber, and the chamber's oxygen concentration is monitored and kept below about 25%. Even there, a facility may restrict a few items for other reasons — ask what applies to you.
Will it help with a condition that is not on the cleared list?
Maybe — and maybe not. Some off-label uses have reasonable evidence behind them; many do not. Off-label use is a legitimate clinical decision, but it should be framed as an experiment with a defined endpoint, not a guaranteed outcome. Be sceptical of anyone promising a cure for a long list of unrelated conditions.
Is the dolphin in the animation real?
No. It is an animation — a friendly way of saying that treatment happens in a calm, supervised setting. It makes no claim about how HBOT feels, and it is not a picture of any real chamber, patient or outcome.