HBOT Safety · Screening · Side Effects
Is Hyperbaric Oxygen Therapy Safe?
Hyperbaric Oxygen Therapy has a long history of clinical use and is generally well tolerated when appropriate screening, equipment and operating procedures are in place.
But HBOT involves both increased atmospheric pressure and increased oxygen exposure, so good safety is not simply about the chamber itself.
It starts with choosing the right person, the right protocol and the right operating environment.
The Short Answer
Yes — HBOT Is Generally Well Tolerated
Like any therapy that changes pressure and oxygen exposure, HBOT has recognised risks and situations where extra care is needed.
Most people tolerate appropriately delivered HBOT well. Good screening and operating procedures are designed to identify potential problems before a session begins and reduce avoidable risk during treatment.
The most familiar issue for many first-time users is simply the change in pressure as the chamber begins to pressurise.
What Makes HBOT Safe?
Safety Has Three Parts
Your First Session
What Does HBOT Usually Feel Like?
During Pressurisation
You will usually notice pressure changing in your ears as the chamber pressurises. It is often compared with the sensation during aircraft take-off or landing. You are shown how to equalise your ears before starting.
Once at Pressure
Once the chamber reaches its operating pressure, the pressure-change sensation settles. The remainder of the session is generally calm, with the chamber maintaining a stable environment until decompression begins.
Pressure & Equalisation
Why Your Ears Matter
The middle ear contains air, so pressure needs to equalise as the surrounding chamber pressure changes.
Middle-ear barotrauma is one of the best-known pressure-related complications of HBOT, particularly if someone cannot equalise effectively.
This is why you should never feel that you have to “push through” painful ear pressure. Pressurisation can be slowed or stopped and the issue addressed.
Possible Side Effects
What Risks Should You Know About?
Most recognised HBOT side effects are related either to changing pressure or increased oxygen exposure.
More Commonly Discussed
Ear or Sinus Discomfort
Pressure changes can cause ear or sinus discomfort and, if equalisation is unsuccessful, barotrauma. Screening and learning how to equalise are important preventative steps.
Individual Response
Confinement Anxiety
Some people feel anxious in an enclosed chamber. Familiarisation, understanding how the chamber works and knowing how to communicate or end a session can make a significant difference.
Repeated Exposure
Temporary Vision Changes
Temporary myopic changes can occur during repeated hyperbaric exposure. These are recognised oxygen-related effects and are generally reversible after HBOT stops.
Uncommon but Important
Oxygen Toxicity
High oxygen partial pressures can produce neurological or pulmonary oxygen toxicity. Modern protocols manage oxygen exposure to reduce this risk, but it remains one reason pressure and duration should be properly controlled.
Screening Before HBOT
Who Needs Additional Assessment?
Screening does not mean looking for reasons to exclude everybody. It means identifying circumstances where HBOT needs to be avoided, delayed or adapted.
Untreated pneumothorax is the recognised absolute contraindication to HBOT. Other conditions are assessed individually rather than being treated as automatic exclusions.
Oxygen & Fire Safety
Why There Are Strict Rules About What Goes Inside
Oxygen does not ignite by itself, but it supports combustion. In oxygen-enriched environments, materials can ignite more easily and burn more rapidly.
That is why hyperbaric safety includes strict control of ignition sources, electronics, batteries and unsuitable products inside the chamber.
These rules are not unnecessary restrictions. They are a core part of responsible chamber operation.
How ReWell Approaches Safety
Safety Starts Before the Chamber Is Switched On
Whether you attend ReWell's Naas clinic or use one of our chambers at home, the safety process starts before your first session.
Screening
Your health history and suitability are reviewed before HBOT is recommended.
Personalised Protocol
Pressure, session frequency and pacing are considered around your circumstances.
Safety Guidance
You are shown how the chamber works, how to equalise and what can and cannot go inside.
Ongoing Support
ReWell remains available throughout your programme if questions or concerns arise.
Choosing an HBOT Provider
Questions Worth Asking Before You Start
Safety Starts With Guidance
Your HBOT Programme, Guided by Davitt
ReWell's HBOT programmes are guided by Davitt Meenaghan, IBUM-certified Hyperbaric Safety Officer.
“Safety isn't about making HBOT complicated. It's about making sure the person is suitable, the chamber is used properly and you know exactly what to do before you begin.”
Davitt guides ReWell clients through suitability, pressure equalisation, chamber operation, device restrictions and the practical safety procedures needed for both clinic and home HBOT.
If you are renting a chamber, that guidance continues after installation rather than ending when the equipment arrives.
Speak With Davitt →Further Reading
HBOT Safety & Patient Selection References
Hyperbaric Oxygen Therapy Contraindications
Updated StatPearls review covering absolute and relative contraindications to HBOT and the role of pre-treatment evaluation.
NCBI Bookshelf NBK557661 →Hyperbaric Patient Selection
Overview of patient screening, contraindications, clinical requirements and appropriate hyperbaric patient selection.
NCBI Bookshelf NBK499820 →Hyperbaric Complications
Current overview of pressure-related complications, oxygen toxicity, confinement anxiety and other recognised adverse effects.
NCBI Bookshelf NBK459191 →Common Questions
HBOT Safety FAQs
Is hyperbaric oxygen therapy safe?
HBOT is generally well tolerated when appropriate screening, equipment and operating procedures are in place. Like any therapy involving pressure and oxygen, it has recognised risks, which is why screening and clear safety protocols matter.
What is the most common problem people experience with HBOT?
Ear discomfort associated with pressure equalisation is one of the most commonly discussed issues. If the ears cannot equalise properly, pressure can cause middle-ear barotrauma. Learning equalisation techniques and slowing or stopping pressurisation if needed can help reduce this risk.
Who should not use HBOT?
Untreated pneumothorax is the recognised absolute contraindication. Other medical conditions, medications, lung issues and implanted devices may require individual assessment before HBOT rather than automatically ruling it out.
Can you use HBOT if you have a cold or blocked sinuses?
Congestion can make pressure equalisation more difficult and increase the risk of ear or sinus barotrauma. If you develop a cold, sinus symptoms or significant congestion, discuss this with ReWell before your session.
Can phones go inside a hyperbaric chamber?
ReWell does not allow phones, smartwatches, tablets or similar battery-powered electronic devices inside its chambers. Controlling electronics and potential ignition sources is part of the hyperbaric safety process.
Can HBOT affect your eyesight?
Repeated hyperbaric oxygen exposure can sometimes cause temporary changes in short-sightedness. These changes are generally reversible after treatment finishes, although any new visual symptoms should be discussed with the treating team.
Can HBOT cause oxygen toxicity?
Oxygen toxicity is a recognised potential complication of elevated oxygen exposure. Risk depends on factors including pressure, duration and cumulative exposure, which is why hyperbaric protocols control these variables.
Is home HBOT safe?
Safe home HBOT depends on appropriate screening, correct chamber setup, clear operating guidance, strict device and ignition rules and access to support. ReWell provides installation, safety guidance and ongoing support with its home rental programmes.
Start With Confidence
New to HBOT? Start With the Right Guidance
Read ReWell's complete safety standards, experience your first session at our Naas clinic, or speak with Davitt if you have questions about suitability or safe HBOT access at home.
This article is for general educational purposes and is not a substitute for individual medical assessment. HBOT may not be suitable for everyone. Medical history, medications, lung health, implanted devices and other relevant circumstances should be reviewed before starting hyperbaric oxygen therapy.