Long COVID · Post-Viral Fatigue · HBOT Research · 8 Min Read
HBOT for Long COVID & Post-Viral Fatigue: What the Research Shows
Long COVID can look very different from one person to another. For some, fatigue dominates. For others it is brain fog, reduced exercise tolerance, pain, poor concentration, disrupted sleep or a feeling that recovery has simply stalled.
That complexity is one reason Hyperbaric Oxygen Therapy (HBOT) has attracted growing research interest.
HBOT increases the amount of oxygen dissolved in blood plasma and is being investigated for its potential effects on brain function, cellular energy, oxygenation, pain, fatigue and wider recovery.
See What the Research Shows ↓A Complex Recovery Picture
Why Is HBOT Being Studied for Long COVID?
Long COVID is not one symptom and it is unlikely to be explained by one single biological process.
People can experience very different combinations of fatigue, cognitive problems, pain, headaches, disrupted sleep, breathlessness and reduced physical capacity.
HBOT is interesting to researchers because its physiological effects extend beyond simply increasing the oxygen carried by red blood cells.
Under increased atmospheric pressure, considerably more oxygen can dissolve directly into blood plasma, temporarily increasing oxygen availability throughout the body.
The Physiological Starting Point
Increased Pressure + Oxygen
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More Oxygen Dissolved in Plasma
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Increased Oxygen Availability
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Potential Effects on Brain Function, Metabolism & Recovery
This is why researchers are examining HBOT across several of the areas that can be relevant to persistent post-COVID symptoms.
The Science
What Are Researchers Looking At?
The interest in HBOT for Long COVID is broader than the idea that “more oxygen fixes fatigue”.
Researchers are examining how repeated exposure to increased oxygen under pressure may influence several overlapping physiological processes.
Cellular Energy
Oxygen is fundamental to aerobic ATP production — the process cells use to generate energy for normal activity and recovery.
Brain Function
Studies are investigating changes in cognition, attention, executive function and brain perfusion following HBOT.
Inflammatory Processes
Hyperbaric oxygen can influence biological signalling involved in inflammatory and recovery responses.
Oxygenation & Recovery
Increasing dissolved oxygen creates a temporary physiological environment that may influence tissue and neurological recovery processes.
These mechanisms help explain why HBOT is being investigated. But for someone considering it, the human clinical research matters more than theory alone.
The Research
What Have Human Studies Found?
HBOT has now been studied in people living with persistent symptoms after COVID-19, including through randomised controlled trials and systematic reviews.
The research is still developing, but several findings are encouraging — particularly around cognition, fatigue, energy, sleep, pain and quality of life.
2024 Systematic Review · 10 Clinical Studies
Most Included Studies Reported Improvement in Long COVID Symptoms
A 2024 systematic review examined the available clinical evidence for HBOT in Long COVID.
The researchers identified 10 clinical studies, including three completed randomised controlled trials as well as observational and pre-post studies.
Most of the included studies reported improvements in one or more areas including quality of life, fatigue, cognition, neuropsychiatric symptoms and cardiopulmonary function.
The authors concluded that HBOT had shown benefits across Long COVID symptoms while calling for larger rigorous trials to refine indications, protocols and follow-up.
View the 2024 systematic review on PubMed →Randomised Double-Blind Sham-Controlled Trial · 73 Patients
Cognition, Energy, Sleep & Pain
One of the most important individual studies was a randomised, double-blind, sham-controlled trial involving 73 people with ongoing post-COVID symptoms for at least three months.
Participants in the HBOT group received 40 sessions.
Compared with the sham group, researchers reported significant improvements in several areas:
The clinical changes were also associated with changes in brain MRI perfusion and microstructure, giving researchers further reason to investigate the neurological effects of HBOT in post-COVID conditions.
View the randomised controlled trial on PubMed →2025 Systematic Review · 7 Studies · 199 Participants
Growing Evidence Around Cognitive Symptoms
A 2025 systematic review looked specifically at HBOT and cognitive decline associated with Long COVID.
It included seven studies from seven countries involving 199 participants, incorporating both randomised and observational research.
Across the included studies, improvements were reported in memory, executive function, attention, fatigue and pain.
HBOT protocols varied considerably, with pressures ranging from 2.0 to 2.5 ATA and programmes ranging from 10 to 60 sessions. The review reported minimal side effects and no serious side effects in the included studies.
View the 2025 systematic review on PubMed →Long COVID research is increasingly asking not only whether symptoms change, but what may be happening to cognition, energy, pain and neurological recovery along the way.
Taken together, the human evidence provides a meaningful basis for continued research into HBOT for Long COVID.
It also shows why this cannot be reduced to a single protocol or a promise that everyone will respond in exactly the same way.
An Important Detail
Why Protocol Matters
One of the clearest lessons from Long COVID research is that “HBOT” does not describe one universal programme.
Studies have used different chamber pressures, oxygen exposures and numbers of sessions. The 2025 systematic review found programmes ranging from 10 to 60 sessions.
This matters because a 2025 randomised trial involving 101 people tested a shorter programme of 10 sessions across different combinations of pressure and oxygen and did not find significant differences between the groups in symptoms, functional scores or cognitive performance.
That result sits alongside other trials and reviews reporting positive findings — and reinforces why pressure, session number, protocol and the outcomes being measured need to be considered when interpreting Long COVID research.
For someone considering HBOT, this is also why access and frequency matter. A programme that is practical enough to complete can be very different from occasional or sporadic sessions.
In Practice
What Does This Mean if You Are Considering HBOT?
Long COVID can affect people in very different ways, so the starting point should be your symptom pattern, medical history, current health and what you are hoping to support.
Someone primarily dealing with cognitive fatigue and brain fog may have a very different experience from someone whose biggest challenge is physical fatigue, pain or reduced exercise tolerance.
It also matters how frequently you can realistically access HBOT.
For some people, starting with a clinic session is the simplest way to experience HBOT. For others considering a repeated programme, having a chamber at home can remove the physical and practical burden of travelling to a clinic for every session.
Making It Personal
The Right Starting Point Depends on You
Long COVID symptoms can overlap with other medical conditions. That makes appropriate assessment particularly important when symptoms are persistent, changing or unexplained.
If HBOT is being explored, the conversation should focus on the individual rather than assuming one programme suits everyone.
Your Main Symptoms
Fatigue, brain fog, pain, sleep problems and reduced exercise tolerance can create very different recovery priorities.
Your Medical History
Screening and individual circumstances matter before beginning hyperbaric oxygen therapy.
Your Goals
Understanding what you are hoping to support makes the conversation around HBOT more useful and specific.
Practical Access
Research programmes frequently involve repeated sessions, making frequency, travel and home access important practical considerations.
If repeated HBOT makes sense for your circumstances, the next question is how you want to access it.
HBOT Access in Ireland
Start in Clinic. Continue at Home. Or Explore Long-Term Ownership.
ReWell gives you different ways to access HBOT depending on how regularly you want to use it and what works best around your health, energy and everyday life.
Try
Experience HBOT in Clinic
New to HBOT? Start at the ReWell clinic in Naas, Co. Kildare, experience a session and understand what HBOT involves before considering more regular access.
60 minute session €85 incl. VAT
Book an HBOT Session →Rent
Regular HBOT at Home
Home rental can make repeated HBOT considerably easier for people managing fatigue or limited energy by removing the need to travel to a clinic for every session.
From €1,229/month incl. VAT
Explore Home HBOT Rental →Own
Long-Term HBOT Access
For people who want HBOT available long term, ReWell supplies a range of soft-shell and hard-shell hyperbaric chambers for home use.
From €9,999 excl. VAT
Explore HBOT Chambers →
Home access can make repeated HBOT easier to fit around energy levels and everyday life.
Guidance Matters
Your HBOT Programme, Guided by Davitt Meenaghan
ReWell’s HBOT programmes are guided by Davitt Meenaghan, IBUM-certified Hyperbaric Safety Officer.
“With Long COVID, there isn't one symptom or one experience. The starting point is understanding the person, what they are dealing with and what they want from HBOT.”
Davitt helps clients understand screening, chamber options, pressure, frequency, safe use and the practical side of accessing HBOT.
For people dealing with fatigue or reduced capacity, the practical side matters too. The best option may be trying HBOT in clinic first, or it may be exploring home access where repeated travel would make regular sessions difficult.
Talk to Davitt — Book a Free Discovery Call →Common Questions
HBOT & Long COVID FAQs
Is HBOT being researched for Long COVID?
Yes. HBOT has been investigated in clinical studies involving people with persistent post-COVID symptoms. Research has examined areas including cognition, fatigue, energy, sleep, pain, quality of life and cardiopulmonary function.
What does the Long COVID research show?
A 2024 systematic review identified 10 clinical studies and reported that most found improvements in one or more areas including quality of life, fatigue, cognition, neuropsychiatric symptoms and cardiopulmonary function. A 2025 systematic review of seven studies and 199 participants reported improvements in memory, executive function, attention, fatigue and pain.
Has HBOT been tested in a randomised trial for Long COVID?
Yes. A double-blind sham-controlled trial involving 73 people with persistent post-COVID symptoms reported significant improvements following 40 HBOT sessions in global cognitive function, attention, executive function, energy, sleep and pain interference. Other trials using different protocols have produced different results, which is one reason protocol remains an important area of research.
How many HBOT sessions have Long COVID studies used?
Protocols vary considerably. The 2025 systematic review found programmes ranging from 10 to 60 sessions, with pressures ranging from 2.0 to 2.5 ATA. There is not one universally established Long COVID HBOT protocol.
Can HBOT help with Long COVID brain fog?
Cognitive symptoms are one of the main areas being investigated. Human studies have reported changes in memory, attention, executive function and global cognition following HBOT, although research is continuing to establish which people and protocols may benefit most.
Can I rent a hyperbaric chamber at home if I have Long COVID?
ReWell provides home hyperbaric chamber rental across all 32 counties, starting from €1,229 per month. Suitability and screening should be considered before beginning HBOT. Home access can be particularly practical for people who want repeated sessions without travelling to a clinic each time.
Can I try HBOT before renting a chamber?
Yes. New clients can start with an introductory HBOT session at the ReWell Naas or Dublin clinics for €85 incl. VAT before deciding whether more regular access is appropriate for them.
The Bottom Line
Long COVID Is Complex. The HBOT Research Is Becoming More Useful.
Long COVID does not affect everyone in the same way, which makes simple claims about any single recovery approach unhelpful.
What we do now have is a growing body of human research investigating HBOT across some of the symptoms that matter most to people living with Long COVID — including fatigue, cognition, energy, sleep, pain and quality of life.
Some of the findings are encouraging. Other research has shown that outcomes can change depending on the protocol used.
For ReWell, that makes the next question much more useful than simply asking whether HBOT “works”:
Could HBOT be relevant to the symptoms you are experiencing — and what would practical, regular and appropriately guided access look like for you?
Explore Your Options
Considering HBOT for Long COVID or Post-Viral Fatigue?
Learn more about the research, explore HBOT for Long COVID at ReWell or speak with Davitt about whether clinic or home access could be the right starting point for you.
This article is for general educational purposes and does not constitute medical advice. Long COVID symptoms can overlap with other health conditions and should be appropriately assessed. HBOT may not be suitable for everyone. Screening and individual suitability are important before beginning hyperbaric oxygen therapy.