HBOT for Long COVID: What the Latest Research Shows

Months after the initial infection clears, millions of people worldwide continue to live with a bewildering constellation of symptoms — persistent fatigue, cognitive fog, breathlessness, and neurological disturbances that resist conventional treatment. Long COVID, or post-acute sequelae of SARS-CoV-2 (PASC), has emerged as one of the most clinically challenging conditions of our era, affecting an estimated 65 million people globally and placing enormous strain on both individuals and healthcare systems.

Against this backdrop, hyperbaric oxygen therapy (HBOT) has attracted significant scientific attention as a potential pathway to meaningful recovery. HBOT long COVID research has accelerated rapidly, with peer-reviewed trials and clinical observations suggesting that targeted, physician-supervised hyperbaric oxygen protocols may address some of the underlying physiological mechanisms driving post-COVID dysfunction — including neuroinflammation, mitochondrial impairment, and compromised cerebral blood flow.

At Holina Clinic in Koh Phangan, Thailand, our clinical team has been closely monitoring this evolving body of evidence. For patients navigating the exhausting reality of hyperbaric oxygen long haul COVID treatment options, understanding what the science actually supports — and what remains under investigation — is essential to making informed decisions about care.

This article examines the latest research on COVID recovery HBOT, exploring what current studies reveal, which patient profiles may benefit most, and how a personalised, clinically supervised treatment approach can be structured to optimise outcomes safely and effectively.

Understanding Long COVID: A Complex, Multisystem Condition

Long COVID — clinically referred to as Post-Acute Sequelae of SARS-CoV-2 (PASC) — has emerged as one of the most challenging and poorly understood conditions of the post-pandemic era. Affecting an estimated 10 to 30 percent of individuals who contract COVID-19, Long COVID is not a single disease but rather a constellation of persistent symptoms that continue for weeks, months, or even years following the initial acute infection. These symptoms often arise regardless of how severe the original illness was — meaning individuals who experienced only mild COVID-19 can still go on to develop debilitating long-term complications.

The clinical picture of Long COVID is remarkably broad. Patients commonly report a range of symptoms including profound fatigue, post-exertional malaise, cognitive impairment (frequently described as “brain fog”), shortness of breath, sleep disturbances, cardiovascular irregularities such as tachycardia and chest pain, gastrointestinal disruption, and persistent neurological symptoms including headaches, dizziness, and peripheral neuropathy. For many patients, these symptoms are not static — they fluctuate unpredictably, often worsening after physical or cognitive exertion.

From a physiological standpoint, researchers have identified several key mechanisms believed to underlie Long COVID pathology:

• Microvascular damage and endothelial dysfunction: Persistent inflammation and damage to the small blood vessels impair oxygen delivery to tissues throughout the body, contributing to fatigue, cognitive decline, and organ-specific dysfunction.
• Mitochondrial dysfunction: Disrupted cellular energy metabolism has been documented in Long COVID patients, resulting in abnormal ATP production and reduced cellular resilience.
• Chronic neuroinflammation: Imaging studies and cerebrospinal fluid analyses have revealed ongoing inflammatory activity within the central nervous system, directly associated with cognitive symptoms and mood disturbances.
• Immune dysregulation: Aberrant immune activation, including elevated autoantibodies and persistent viral antigen presence, sustains a state of chronic low-grade systemic inflammation.
• Hypoxia at the cellular level: Even patients with normal blood oxygen saturation readings may experience tissue-level hypoxia due to microclot formation and impaired red blood cell function.

This complex, overlapping pathophysiology means that conventional medical approaches — rest, symptomatic management, and standard rehabilitation — often fall short of providing meaningful relief. Patients frequently describe cycling through multiple specialists without receiving a cohesive, mechanistically targeted treatment strategy. It is precisely this therapeutic gap that has driven growing scientific and clinical interest in hyperbaric oxygen therapy as a potential intervention — one that directly addresses several of the core physiological disruptions observed in Long COVID. At Holina Clinic, our physician-supervised HBOT programmes are designed with this multisystem complexity in mind, approaching each patient’s recovery through a personalised, evidence-based clinical lens.

How Hyperbaric Oxygen Therapy Works: The Physiological Mechanisms Behind the Treatment

Hyperbaric oxygen therapy involves breathing 100% pure oxygen inside a pressurised chamber, typically at 1.5 to 3 times normal atmospheric pressure. This controlled environment dramatically increases the amount of oxygen dissolved directly into the blood plasma, bypassing the usual reliance on haemoglobin to transport oxygen throughout the body. The result is a significant elevation in tissue oxygen concentration — including in areas where circulation may be compromised or microvascular damage has occurred.

For Long COVID patients, this mechanism is particularly relevant because mounting evidence points to persistent microvascular dysfunction as a central driver of ongoing symptoms. Small blood vessel injury, endothelial inflammation, and the presence of microclots have all been identified in Long COVID patients well beyond the acute phase of infection. HBOT directly addresses these pathological processes through several distinct physiological pathways:

• Neovascularisation: Repeated HBOT sessions stimulate the growth of new blood vessels, helping restore oxygen delivery to hypoxic tissues that have been starved of adequate perfusion since the initial infection.
• Neuroplasticity support: Elevated oxygen levels promote neuronal repair and have been shown in imaging studies to increase cerebral blood flow, which may help explain improvements in cognitive function and brain fog reported by patients following a structured course of treatment.
• Mitochondrial rehabilitation: HBOT appears to assist in restoring mitochondrial function, addressing the cellular energy production failures that many researchers now associate with the profound fatigue characteristic of Long COVID.
• Anti-inflammatory effects: Hyperoxia has been demonstrated to downregulate pro-inflammatory cytokines and reduce oxidative stress markers, targeting the chronic, low-grade inflammation that sustains many post-viral symptoms.
• Immune modulation: Emerging research suggests HBOT influences T-cell activity and supports the normalisation of dysregulated immune responses that persist in a subset of Long COVID patients.

At Holina Clinic, every patient undergoes a thorough clinical evaluation before commencing hyperbaric therapy. Treatment protocols — including pressure levels, session duration, and total number of sessions — are individualised based on symptom profile, medical history, and physician assessment, ensuring that each course of HBOT is both safe and appropriately targeted to the patient’s specific presentation.

What the Latest Clinical Research Reveals About HBOT and Long COVID

The evidence base supporting hyperbaric oxygen therapy for Long COVID has grown substantially over the past three years, with several peer-reviewed studies offering clinically meaningful insights into both its mechanisms and its real-world outcomes. Among the most significant contributions is a randomised controlled trial published in Nature Communications in 2022, conducted by researchers at Tel Aviv University. This study followed 73 Long COVID patients who received 40 sessions of HBOT over a period of two months. The results demonstrated statistically significant improvements in cognitive function, energy levels, sleep quality, and pain thresholds — alongside measurable neurological changes confirmed by brain imaging.

What makes this research particularly compelling from a clinical standpoint is the objective data underpinning the subjective improvements. Participants showed increased cerebral blood flow and enhanced neuroplasticity on MRI scans, suggesting that HBOT is not merely addressing symptoms but may be supporting genuine tissue-level recovery. These are not anecdotal reports — they are quantifiable biological changes observed under controlled conditions.

Additional research has focused on several key physiological mechanisms through which HBOT may benefit Long COVID patients:

• Mitochondrial rehabilitation: Hyperbaric oxygen exposure has been shown to support mitochondrial function, addressing the cellular energy deficits that many researchers now associate with post-viral fatigue syndromes.
• Reduction of neuroinflammation: Studies indicate that HBOT can modulate inflammatory markers in neural tissue, potentially alleviating the cognitive symptoms commonly described as brain fog.
• Angiogenesis stimulation: Repeated pressurised oxygen sessions appear to promote the formation of new blood vessels, improving microcirculation in tissues that remain oxygen-deprived following infection.
• Immune system recalibration: Emerging evidence suggests HBOT may help rebalance dysregulated immune responses that persist long after the initial SARS-CoV-2 infection has resolved.

It is important to acknowledge that the research field is still evolving. Sample sizes in existing studies remain relatively modest, and larger multicentre trials are currently underway. However, the consistency of findings across independent research groups, combined with the well-established safety profile of physician-supervised HBOT, positions this therapy as one of the most scientifically credible options currently available for Long COVID management.

What Happens During an HBOT Session at a Clinical Setting

For patients considering hyperbaric oxygen therapy as part of their Long COVID recovery, understanding the clinical process helps set realistic expectations and supports informed decision-making. At a physician-supervised facility, HBOT is never a one-size-fits-all intervention. Each patient undergoes a thorough medical assessment before treatment begins, including a review of symptom history, cardiovascular status, pulmonary function, and any contraindications such as untreated pneumothorax or certain medications that increase oxygen toxicity risk.

The therapy itself takes place inside a hyperbaric chamber — either a monoplace unit designed for a single patient or a multiplace chamber accommodating several individuals simultaneously. Patients breathe 100% pure oxygen through a mask or hood while the chamber is pressurised to between 1.5 and 2.5 atmospheres absolute (ATA), depending on the personalised treatment protocol established by the supervising physician. For Long COVID applications, many clinical protocols currently under investigation utilise pressures in the 2.0 ATA range, with sessions typically lasting 60 to 90 minutes.

A standard therapeutic course generally involves multiple sessions delivered over several weeks. Research protocols published in peer-reviewed literature — including the landmark Tel Aviv University trial — have used 40 daily sessions, five days per week, as a structured intervention period. Clinical teams monitor patients throughout each session, with trained personnel available to respond to any discomfort, including ear pressure equalisation difficulties, which are common during the initial pressurisation phase and are typically managed with simple techniques.

Patients can expect the following elements as part of a well-structured HBOT programme for Long COVID:

• Pre-treatment evaluation: Baseline cognitive testing, neurological assessment, and symptom scoring to establish measurable benchmarks
• Individualised pressure protocols: Dosing tailored to symptom profile and treatment tolerance under physician guidance
• Mid-course reassessment: Clinical check-ins to evaluate response and adjust the programme accordingly
• Post-course follow-up: Outcome measurement using validated tools to track neurological, cognitive, and functional improvements
• Complementary support: Integration with nutritional guidance, sleep optimisation, and adjunct therapies where clinically appropriate

This structured, evidence-informed approach ensures that each patient receives clinically grounded care rather than a generic wellness experience.

What to Expect From an HBOT Protocol for Long COVID

For patients considering hyperbaric oxygen therapy as part of their Long COVID recovery, understanding the structure of a clinical protocol is essential. At Holina Clinic, every HBOT programme begins with a comprehensive physician-led assessment, reviewing symptom history, cardiovascular health, pulmonary function, and any contraindications before a single session begins. This clinical oversight is not a formality — it directly shapes the personalised treatment plan that follows.

A standard HBOT protocol for Long COVID typically involves daily sessions conducted five days per week over four to six consecutive weeks, totalling 40 to 60 individual sessions. Each session lasts approximately 90 minutes, during which patients breathe 100% pure oxygen inside a pressurised chamber at 1.5 to 2.0 atmospheres absolute (ATA). These specific pressure parameters are not arbitrary — they are calibrated to reach oxygen partial pressures that meaningfully influence neuroinflammation, mitochondrial recovery, and microvascular repair, the three primary pathological drivers identified in Long COVID research.

Patients can generally expect the following across their treatment course:

• Weeks one to two: An adaptation phase during which the body adjusts to hyperbaric conditions. Some patients report mild ear pressure or transient fatigue, which typically resolves quickly with proper equalisation techniques guided by clinical staff.
• Weeks three to four: Many patients begin noticing measurable improvements in cognitive clarity, sleep quality, and exercise tolerance as neurological and vascular repair processes accumulate.
• Weeks five to six: The consolidation phase, where therapeutic gains often become more consistent. Fatigue patterns frequently stabilise and post-exertional malaise episodes may decrease in both frequency and severity.

Progress is monitored throughout the protocol using validated clinical tools, including cognitive performance assessments and symptom burden questionnaires aligned with those used in peer-reviewed Long COVID research. This data-driven approach allows the supervising physician to adjust session parameters or integrate complementary therapies — such as nutritional IV support or functional rehabilitation — where clinically appropriate.

The goal is not simply to complete a course of sessions, but to deliver a structured, responsive, and medically supervised pathway toward meaningful functional recovery.

Taking the Next Step: Is HBOT Right for Your Long COVID Recovery?

Deciding whether hyperbaric oxygen therapy is appropriate for your Long COVID symptoms is a decision best made in close collaboration with an experienced medical team. While the emerging body of clinical evidence is genuinely encouraging, HBOT is not a universal intervention, and candidacy depends on a thorough assessment of your symptom profile, medical history, comorbidities, and current treatment plan. At Holina Clinic, every patient undergoes a comprehensive intake evaluation — including detailed symptom mapping, cardiovascular screening, pulmonary function review, and neurological assessment — before any protocol is recommended.

Understanding what a realistic treatment journey looks like is an important part of informed decision-making. Based on current clinical protocols and the research emerging from leading hyperbaric medicine centres, most Long COVID patients considered for HBOT can expect the following:

• Initial consultation and baseline diagnostics: Physician-led assessment including relevant biomarkers, cognitive function screening, and exercise tolerance evaluation to establish a clear clinical baseline
• Individualised protocol design: Pressure depth, session duration, oxygen concentration, and total session number are calibrated to your specific condition — not a standardised one-size-fits-all schedule
• Typical treatment course: Current evidence-informed protocols generally involve 40 to 60 sessions, delivered once daily on weekdays, each lasting approximately 90 minutes at 1.5 to 2.4 atmospheres absolute
• Concurrent integrative support: HBOT is most effective when delivered alongside nutritional medicine, sleep optimisation, carefully graded physical rehabilitation, and psychological support where indicated
• Ongoing clinical monitoring: Regular physician check-ins throughout the programme allow the protocol to be adjusted in real time based on your physiological response and evolving symptom presentation
• Post-treatment reassessment: Objective outcome measures are repeated at programme completion to quantify functional improvements and guide any further recommendations

Long COVID can be an isolating and deeply frustrating condition, particularly when conventional medicine has offered limited relief. Physician-supervised HBOT, delivered within a structured, evidence-informed clinical environment, represents one of the most scientifically substantiated emerging approaches currently available to those living with persistent post-COVID sequelae. If you are experiencing ongoing fatigue, cognitive difficulties, breathlessness, or exercise intolerance more than twelve weeks after your acute infection, we encourage you to speak with our medical team to explore whether hyperbaric oxygen therapy belongs in your recovery pathway.

The emerging body of research surrounding hyperbaric oxygen therapy and Long COVID represents one of the most clinically compelling developments in post-viral rehabilitation medicine. Peer-reviewed trials continue to demonstrate measurable improvements in neurological function, mitochondrial efficiency, cerebral blood flow, and systemic inflammation — all of which are central mechanisms in the persistent symptom burden experienced by Long COVID patients. While individual responses vary and physician-supervised assessment remains essential, the evidence increasingly supports HBOT as a meaningful component of a structured, personalised recovery protocol.

At Holina Clinic in Koh Phangan, Thailand, our experienced medical team integrates hyperbaric oxygen therapy within a comprehensive, evidence-based framework tailored to each patient’s clinical profile, symptom history, and recovery goals. Every treatment plan is developed under direct clinical oversight, combining HBOT with complementary therapeutic modalities to support whole-body restoration.

If you are experiencing persistent fatigue, cognitive difficulties, or other Long COVID symptoms that have not responded to conventional care, we invite you to contact Holina Clinic today to schedule a personalised medical consultation and take a considered, clinically guided step toward recovery.