The ReWell Guide to HBOT
Hyperbaric Oxygen Therapy (HBOT): A Complete Guide to How It Works, Benefits, Research & Safety
What actually happens inside a hyperbaric chamber? Why does pressure matter? And what does the research really tell us? This guide brings together the science, practical considerations and different ways to access Hyperbaric Oxygen Therapy in Ireland.
Start Here
What Is Hyperbaric Oxygen Therapy?
At its simplest, hyperbaric therapy combines increased atmospheric pressure with increased oxygen availability.
A person sits or lies inside a purpose-built chamber while the pressure inside the chamber is gradually increased above normal atmospheric pressure. Depending on the type of chamber and protocol, oxygen may be delivered at different concentrations.
The combination of pressure and oxygen changes the physical behaviour of oxygen in the body. In traditional medical HBOT, breathing high-concentration oxygen under pressure substantially increases the amount of dissolved oxygen carried in the blood plasma, in addition to the oxygen already transported by haemoglobin.
HBOT is not simply about “breathing more oxygen”. Pressure is a fundamental part of the process because it changes how oxygen is dissolved and delivered within the body.
The Fundamentals
How Does HBOT Work?
HBOT works through two connected variables: pressure and oxygen. Increasing atmospheric pressure affects gases in the body, while increasing the partial pressure of oxygen changes the amount of oxygen available in blood and tissues.
Pressure Increases
The chamber is gradually pressurised above normal atmospheric pressure. This controlled increase in pressure is measured in atmospheres absolute, or ATA.
Oxygen Availability Rises
Under appropriate hyperbaric conditions, more oxygen can dissolve into the liquid component of the blood, increasing oxygen availability beyond that carried by haemoglobin alone.
Tissue Oxygen Changes
Where blood flow is sufficient to deliver that oxygen, tissue oxygen levels can rise. These changes form part of the physiological basis for established and developing applications of HBOT.
Hyperbaric chambers are available in different formats, pressure ranges and configurations.
Inside the Body
What Happens to the Body During HBOT?
The science of HBOT extends beyond simply supplying oxygen. Research into hyperbaric physiology describes several interconnected effects produced by pressure, increased oxygen partial pressure and the body's response to those changes.
More Dissolved Oxygen
Under hyperbaric conditions, oxygen can dissolve into plasma at higher concentrations. This increases the amount of oxygen available for delivery through the circulation.
Higher Tissue Oxygen
Increased oxygen availability in the circulation can raise tissue oxygen levels where perfusion is sufficient to deliver it.
Cellular Signalling
Hyperoxia influences reactive oxygen and nitrogen species. In controlled amounts these molecules also participate in cell-signalling pathways associated with physiological adaptation and repair processes.
Repair & Vascular Processes
Research has examined HBOT in relation to growth-factor signalling, wound repair and angiogenesis — the formation of new blood vessels — particularly in areas where HBOT already has established medical uses.
Benefits & Evidence
What Is HBOT Used For?
This is where it is important to separate established medical applications from areas where research is still developing.
Hyperbaric oxygen has recognised clinical applications in conventional hyperbaric medicine. These include conditions such as decompression sickness, carbon monoxide poisoning, selected problem wounds, delayed radiation injury, refractory osteomyelitis and certain other specific conditions.
At the same time, researchers continue to investigate HBOT across a much broader range of areas. The strength of evidence varies considerably by condition, treatment pressure, oxygen concentration, protocol and patient population.
Recovery & Tissue Repair
HBOT research includes wound healing, tissue oxygenation, post-surgical recovery and repair processes. The quality of evidence depends heavily on the particular condition being studied.
Explore Recovery →Sport & Performance Recovery
Research is examining whether hyperbaric exposure may have a role in exercise recovery, muscle recovery and selected sports-related injuries. It should not be presented as proven to prevent injury or guarantee faster return to play.
Explore Athletic Recovery →Brain & Neurological Research
HBOT is being studied in areas involving brain metabolism, neuroplasticity, traumatic brain injury and post-concussion symptoms. Findings vary between conditions and study protocols.
Explore Brain & Concussion Research →Long COVID & Post-Viral Symptoms
Emerging human studies have explored HBOT in relation to cognition, fatigue, quality of life and other persistent symptoms following COVID-19. This remains an evolving area of research.
Explore Long COVID →Chronic Pain & Fibromyalgia
Research has explored HBOT in fibromyalgia and chronic pain populations, including possible effects involving pain processing, cellular metabolism and inflammatory pathways.
Explore Chronic Pain →Healthy Ageing & Longevity
HBOT is also being researched in relation to aspects of ageing biology and cognitive function. These findings are interesting, but they should not be interpreted as evidence that HBOT reverses ageing or extends lifespan.
Explore the Research →The Science
We can explain with reasonable confidence what increased pressure and oxygen do physiologically: they alter oxygen partial pressure, increase dissolved oxygen under appropriate conditions and influence cellular signalling and tissue oxygenation.
The Research
Whether those mechanisms translate into a meaningful clinical benefit depends on the condition, the individual and the treatment protocol. That is why ReWell looks at condition-specific human research rather than treating every proposed use of HBOT as equally established.
Understanding Pressure
What Does ATA Mean in Hyperbaric Therapy?
Hyperbaric chamber pressure is normally described in ATA — atmospheres absolute. Normal atmospheric pressure at sea level is approximately 1.0 ATA. A chamber operating above this increases the pressure around the body.
You may see chambers described as 1.3 ATA, 1.5 ATA, 2.0 ATA or 2.5 ATA. These numbers matter — but a higher number does not automatically mean a better treatment.
| Pressure | Broad Context |
|---|---|
| 1.3 ATA | Lower-pressure or mild hyperbaric exposure. |
| 1.5 ATA | Common in some lower-pressure soft-shell and wellness settings. |
| 2.0 ATA | Higher-pressure hyperbaric exposure available in suitable hard-shell systems. |
| 2.5 ATA | Higher-pressure protocols requiring appropriate equipment, training and safety oversight. |
Pressure is only one part of a protocol. Oxygen concentration, session duration, frequency, chamber type and the reason for using HBOT all matter.
Chamber Types
Soft-Shell vs Hard-Shell Hyperbaric Chambers
Hyperbaric chambers are not all the same. One of the most important practical distinctions is between lower-pressure soft-shell systems and hard-shell chambers capable of operating at higher pressures.
Portable chamber formats can make regular home access more practical for suitable users.
Soft-Shell Chambers
Soft-shell chambers are portable systems generally designed for lower-pressure hyperbaric use. Their size, installation requirements and accessibility make them particularly relevant for home rental and ownership.
ReWell offers lying/hybrid, seated and accessible soft-shell options, allowing the chamber format to be matched more closely to the person, household and available space.
Hard-Shell Chambers
Hard-shell chambers use rigid construction and can operate at higher pressures. Depending on the model, these may be appropriate for private, professional, clinic, sports, recovery or wellness settings where the required installation, operational and safety considerations can be met.
The right choice is therefore not simply “soft or hard”. It depends on why you are considering HBOT, how frequently it will be used, required pressure, space, mobility, budget and the level of operational support required.
What to Expect
What Happens During an HBOT Session?
Although chamber types differ, the basic experience follows a similar pattern. You enter the chamber, the pressure is gradually increased, you spend the prescribed period at pressure, and the chamber is then slowly depressurised.
During pressurisation, your ears may feel similar to how they feel during take-off or landing in an aircraft. You will normally be shown techniques for equalising pressure in your ears before beginning.
Once at pressure, the experience is generally passive. Depending on the chamber, you may sit or lie down and relax for the duration of the session.
HBOT protocols are not one-size-fits-all. Session pressure, duration, frequency and total number of sessions should be considered in the context of the individual and the reason HBOT is being used.
Your Programme
How Many HBOT Sessions Do You Need?
There is no universal number of HBOT sessions that is right for everyone.
Some established medical protocols involve defined treatment schedules. Outside those settings, the appropriate frequency and duration depend on the purpose of treatment, chamber pressure, individual circumstances, response and the evidence relevant to the particular condition.
This is one reason ReWell places emphasis on a personalised programme rather than simply selling individual chamber sessions or assuming that the same schedule is appropriate for every person.
For people who are likely to use HBOT regularly, home rental can also remove some of the practical barriers involved in repeatedly travelling to a clinic.
Safety First
Is Hyperbaric Oxygen Therapy Safe?
HBOT is generally well tolerated when the person, equipment and protocol are appropriate, but it is not risk-free. Pressure and elevated oxygen exposure create specific safety considerations that should be understood before treatment begins.
Ear & Sinus Pressure
Pressure-related ear discomfort and barotrauma are among the more common adverse effects. Proper equalisation and controlled pressurisation are important.
Oxygen Exposure
Higher oxygen exposures can produce oxygen-related adverse effects. Appropriate pressure, duration and protocol selection therefore matter.
Suitability Screening
Untreated pneumothorax is a recognised absolute contraindication. Medications, respiratory conditions, recent surgery, pregnancy and other medical circumstances may also require individual assessment.
Chamber Safety
Oxygen and pressurised environments require strict attention to ignition sources, electronics, batteries, clothing, equipment and manufacturer operating procedures.
Accessing HBOT in Ireland
Try It. Rent It. Or Own Your Chamber.
ReWell offers three ways to access HBOT, allowing you to start at the level that makes sense for your circumstances rather than committing to one route from the beginning.
Personally Guided
Not Sure Where to Start?
Davitt Meenaghan · IBUM-Certified Hyperbaric Safety Officer
Choosing HBOT is not just about choosing a chamber. Pressure, oxygen delivery, frequency, chamber type, safety and your reason for considering HBOT all need to make sense together.
Davitt can talk you through the available options and help you understand whether clinic sessions, home rental or ownership is the most appropriate place to begin.
Selected References
Research Behind the Fundamentals
This guide is designed as an accessible introduction rather than an exhaustive systematic review. These sources provide useful background on HBOT mechanisms, clinical applications and safety.
Camporesi EM, Bosco G. Mechanisms of action of hyperbaric oxygen therapy. Undersea Hyperb Med. 2014;41(3):247–252. PMID 24984320 →
Thom SR. Hyperbaric oxygen: its mechanisms and efficacy. Plast Reconstr Surg. 2011. PMID 21200283 →
Zhang Y et al. Adverse effects of hyperbaric oxygen therapy: a systematic review and meta-analysis. Front Med. 2023. PMID 37275378 →
Undersea & Hyperbaric Medical Society. Hyperbaric Oxygen Therapy Indications. View UHMS Indications →
Frequently Asked Questions
HBOT: The Practical Questions
Is HBOT the same as simply breathing oxygen?
No. Hyperbaric therapy involves increased atmospheric pressure. The combination of pressure and oxygen exposure changes oxygen partial pressure and, under appropriate conditions, increases the amount of oxygen dissolved in plasma.
Does a higher ATA mean better HBOT?
No. Higher pressure is not automatically better. The appropriate pressure depends on the chamber, oxygen delivery, intended use, protocol and individual circumstances.
Can I have a hyperbaric chamber at home?
Yes, suitable hyperbaric chambers can be installed for home use. The right option depends on chamber type, available space, accessibility, oxygen equipment, power requirements, safety and how frequently you plan to use it. ReWell provides home chamber rental across Ireland as well as ownership options.
How much does HBOT cost in Ireland?
At ReWell, a new-client introductory clinic session starts from €50 + VAT. Home chamber rental starts from €999 per month, while chamber ownership starts from €9,999. Pricing varies according to the chamber and access option.
How many HBOT sessions will I need?
There is no single answer. Session number and frequency depend on the reason for using HBOT, the protocol, chamber pressure, individual circumstances and response. Some people use a defined course, while others are considering more regular access.
Is HBOT proven for every condition it is used for?
No. HBOT has established medical indications, while many other areas are still being investigated. Evidence quality varies considerably by condition. ReWell separates established physiology from condition-specific research so that emerging evidence is not presented as established fact.
Who should not use HBOT?
Untreated pneumothorax is a recognised absolute contraindication. Other medical conditions, medications, pregnancy, recent procedures and individual circumstances may require additional assessment before HBOT. Suitability should always be considered before beginning.
The Bottom Line
HBOT Is Simple in Principle — But the Details Matter
Pressure changes oxygen availability. What matters next is how that physiology is applied.
Hyperbaric Oxygen Therapy has established uses within medicine and a growing body of research across recovery, neurological health, persistent symptoms, sports and other areas. But the evidence is not equally strong for every proposed application.
Understanding the difference between the mechanism, the research and the practical protocol is the best place to start.
At ReWell, that also means looking beyond the chamber itself — at suitability, pressure, oxygen, frequency, safety and whether clinic access, home rental or ownership best fits what you are trying to achieve.
Wondering Whether HBOT Is Right for You?
Speak with Davitt about your goals, the different chamber options and the most practical way to access HBOT through ReWell.
This article is for general educational information only and is not medical advice, diagnosis or treatment. HBOT has established medical applications as well as areas where research is still developing. Individual suitability, potential benefits and risks vary. Speak with an appropriately qualified healthcare professional regarding medical conditions or treatment decisions.