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Emerging Research (Off-list) Level C - Expert Consensus

Long COVID and HBOT

Long COVID (post-COVID condition) is not on Ontario's OHIP-funded list for hyperbaric oxygen therapy (Ontario Schedule of Benefits, as of April 1, 2026); in other provinces, check with the provincial hospital programme. The landmark randomised controlled trial from the Shamir Medical Center group in Israel (Zilberman-Itskovich et al, Scientific Reports 2022) showed cognitive, fatigue, sleep, and pain improvements after 40 HBOT sessions, supported by a dedicated MRI substudy (Catalogna et al, Neuroimage Clinical 2022) and a one-year longitudinal follow-up (Hadanny et al, Scientific Reports 2024) showing durable benefit. Two further Canadian trials are registered in Toronto. Several Canadian private clinics offer HBOT for long COVID on a self-pay basis; clinics that publish prices online list $150 to $365 for a single session for one person (checked October 2026), and each clinic prices a full course itself.

· · Canada Hyperbarics Editorial Team · Sources

Quick Answer

Does HBOT help long covid? Long COVID (post-COVID condition) is not on Ontario's OHIP-funded list for hyperbaric oxygen therapy (Ontario Schedule of Benefits, as of April 1, 2026); in other provinces, check with the provincial hospital programme. The landmark randomised controlled trial from the Shamir Medical Center group in Israel (Zilberman-Itskovich et al, Scientific Reports 2022) showed cognitive, fatigue, sleep, and pain improvements after 40 HBOT sessions, supported by a dedicated MRI substudy (Catalogna et al, Neuroimage Clinical 2022) and a one-year longitudinal follow-up (Hadanny et al, Scientific Reports 2024) showing durable benefit. Two further Canadian trials are registered in Toronto. Several Canadian private clinics offer HBOT for long COVID on a self-pay basis; clinics that publish prices online list $150 to $365 for a single session for one person (checked October 2026), and each clinic prices a full course itself.

Authoritative references: Health Canada on hyperbaric oxygen therapy · UHMS clinical practice guidelines · Canadian regulatory framework

What Is Long COVID?

Post-COVID condition, commonly called long COVID, is a syndrome of persistent symptoms lasting twelve weeks or more after acute SARS-CoV-2 infection that cannot be explained by another diagnosis. The World Health Organization clinical case definition recognises long COVID as a distinct condition, and estimates from the Public Health Agency of Canada and Statistics Canada range from approximately 10 to 20 percent of Canadians with confirmed COVID-19 developing persistent symptoms, depending on the cohort, infection wave, and survey methodology. The clinical picture is heterogeneous, encompassing four broad symptom clusters that often co-exist in the same patient.

The cognitive cluster (often called "brain fog") includes difficulty with memory, concentration, executive function, word-finding, and processing speed. Standardised neuropsychological testing in long COVID cohorts shows measurable deficits in working memory and attention even when patients self-report only mild subjective symptoms. The fatigue and post-exertional malaise cluster includes profound exhaustion that is disproportionate to activity level and is often worsened for days after physical or cognitive exertion, mirroring the post-exertional symptom exacerbation seen in myalgic encephalomyelitis / chronic fatigue syndrome. The autonomic cluster includes postural orthostatic tachycardia syndrome (POTS), inappropriate sinus tachycardia, orthostatic hypotension, and other forms of dysautonomia. The exertional intolerance and cardiopulmonary cluster includes shortness of breath, chest pain, and reduced exercise capacity not fully explained by detectable cardiac or pulmonary disease.

There is no single approved treatment for long COVID. Canadian post-COVID care is delivered through multidisciplinary clinics in major academic centres (UHN Toronto, Vancouver General Hospital, McGill, others), with management focused on symptom-specific rehabilitation, pacing, autonomic-targeted pharmacotherapy where indicated (low-dose beta-blockade or ivabradine for POTS, for example), and graded return-to-activity programmes calibrated to avoid post-exertional crashes. The patient population looking for additional options is large and active, and HBOT has emerged as one of the more-studied off-label adjuncts.

How HBOT Helps

Three overlapping mechanistic hypotheses underpin the rationale for HBOT in long COVID. None is yet proven in large-scale Canadian trials, but each is consistent with both the published RCT evidence and with HBOT's established effects in related conditions.

The first is hypoxia-reperfusion injury and persistent tissue hypoxia. SARS-CoV-2 directly infects vascular endothelial cells through ACE2 receptors, producing widespread endothelial dysfunction that can persist long after viral clearance. Damaged endothelium impairs micro-vascular oxygen delivery, leading to chronic regional hypoxia in the brain, muscle, and other high-demand tissues. HBOT directly reverses this hypoxia during each session by raising plasma-dissolved oxygen content 10- to 15-fold, restoring tissue oxygenation independent of the damaged endothelial supply. Repeated intermittent hyperoxia also stimulates endothelial repair and angiogenesis through VEGF release, supporting longer-term recovery of the microvascular bed.

The second is the microclot and persistent coagulopathy theory. Several research groups (notably Pretorius and colleagues in South Africa) have documented persistent fibrinaloid microclots in long COVID patient samples, with microclots resistant to normal fibrinolysis and capable of obstructing capillary-level perfusion. These microclots may sequester inflammatory mediators and may contribute to the chronic micro-vascular injury underlying both the fatigue and cognitive clusters. HBOT may help by supporting endogenous fibrinolysis, reducing platelet activation, and improving tissue oxygenation downstream of obstructed micro-vessels.

The third is autonomic dysregulation and neuroinflammation. Functional neuroimaging in long COVID cohorts shows altered cerebral blood flow patterns, with hypoperfusion in regions including the brainstem and limbic system. The hypoperfusion may both cause and be caused by the autonomic dysfunction (POTS, orthostatic intolerance) seen clinically. Persistent neuroinflammation, possibly driven by reservoir SARS-CoV-2 antigens or by autoimmune mechanisms triggered by molecular mimicry, may compound the injury. HBOT modulates neuroinflammation, supports regional cerebral blood flow normalisation, and reduces oxidative stress in the central nervous system. The Shamir Medical Center MRI substudies in long COVID patients showed measurable changes in regional blood flow and white-matter integrity after 40 HBOT sessions, supporting this mechanism.

Typical Treatment Protocol

In the 2022 Shamir Medical Center RCT (Zilberman-Itskovich et al), patients received 40 daily sessions. Sessions include scheduled air-breaks (typically three air-breaks of five minutes each) to limit oxygen toxicity. Course length is set by the treating team. Individual session pacing is critical for long COVID patients with significant post-exertional malaise. The travel to and from the clinic, the chamber pressurisation, and the cumulative effect over several weeks can themselves trigger crashes in PEM-prone patients. Many Canadian clinics offering HBOT for long COVID schedule sessions with rest days, allow flexible attendance during flare periods, and provide on-site recovery time after sessions. There is no standardised Canadian protocol because long COVID is not a recognised hyperbaric indication. Each private clinic operates under its own clinical-governance framework, and protocol details (pressure, duration, total sessions, air-break schedule) vary across the country.

Evidence Summary

C

Level C - Expert Consensus

Based on case series and expert opinion

Key Research Findings

  • Long COVID is NOT on Ontario's OHIP-funded list for HBOT (Ontario Schedule of Benefits, as of April 1, 2026); in other provinces, check with the provincial hospital programme. Treatment is on a self-pay basis at private clinics, each of which sets its own price.

  • The Zilberman-Itskovich et al. RCT (Scientific Reports 2022, Shamir Medical Center / Tel Aviv University, PMID 35821512, 73 patients randomised 37 HBOT vs 36 sham) showed statistically significant improvements in global cognitive function, attention, executive function, energy, sleep quality, psychiatric symptoms, and pain interference after 40 daily HBOT sessions. This is the landmark RCT supporting HBOT in long COVID and is the basis for the 40-session protocol used in subsequent trials.

  • The Catalogna et al. dedicated MRI substudy (Neuroimage Clinical 2022, PMID 36208548, same 73-patient cohort) used resting-state functional MRI and diffusion tensor imaging to demonstrate measurable changes in functional and structural brain connectivity after the 40-session HBOT course, providing mechanistic correlates for the clinical improvements seen in the parent trial.

  • The Hadanny et al. one-year longitudinal follow-up (Scientific Reports 2024, PMID 38360929, 31 patients from the original cohort reassessed at approximately 486 days) showed that the clinical improvements seen in the parent 2022 trial persisted at long-term assessment across most domains (quality of life, sleep, neuropsychiatric symptoms, pain), supporting durability of the HBOT benefit.

  • Two Canadian trials of HBOT for long COVID are registered in Toronto: NCT06082518 (randomised sham-controlled, persistent post-COVID symptoms) and NCT06452095 (cognitive and fatigue outcomes); check each listing for its current recruitment status.

  • A 2022 CADTH (Canadian Agency for Drugs and Technologies in Health) review identified HBOT as an emerging therapy for post-COVID condition. Full Canadian guideline endorsement has not occurred, and Canadian regulators have not issued specific clinical guidance for long COVID HBOT to date.

  • In the 2022 Shamir Medical Center RCT (Zilberman-Itskovich et al), patients received 40 daily sessions.

  • Response varies by symptom cluster. Cognitive symptoms (brain fog, executive function) and fatigue show the strongest signal in the published evidence. Autonomic symptoms (POTS, orthostatic intolerance) and exertional intolerance show smaller effect sizes. Patients with predominantly cognitive or fatigue presentations are the best-supported candidates for a course.

Top studies in our database

Highest-evidence-tier studies tagged to this condition in the Canada Hyperbarics research database, ranked by evidence tier (1 = meta-analysis or RCT, 2 = cohort, 3 = case series), most recent first.

Registered trials (ClinicalTrials.gov)

Studies in our database that include a ClinicalTrials.gov registration. Trial registration is a marker of methodological rigour because the protocol, primary outcome, and analysis plan are deposited before enrolment begins.

See all long covid studies in our research database

Active Canadian Trials

The following hyperbaric oxygen trials related to long covid are currently recruiting or active at Canadian sites. Data is pulled live from ClinicalTrials.gov (refreshed every 24 hours). Speak with your physician about whether you might be eligible.

Data source: ClinicalTrials.gov. Trial status updates daily. Eligibility, exclusion criteria, and consent should be discussed with your physician and the trial's principal investigator.

What to Expect from Treatment

Most patients seeking HBOT for long COVID are referred internally by a private clinic after an initial consultation with the clinic's medical staff, or come to a clinic on their own initiative after research and physician discussion. Some Canadian clinics require a physician referral; others require a baseline medical questionnaire and clearance for chamber-related contraindications (untreated pneumothorax, severe COPD with bullous lung disease, uncontrolled cardiac arrhythmia). Pre-treatment work-up at most clinics includes baseline neuropsychological screening (cognitive symptoms), a six-minute walk test or PROMIS fatigue questionnaire (fatigue and PEM), and orthostatic vital signs (autonomic symptoms), so that response can be tracked over the course.

Daily sessions typically begin within one to two weeks of the consultation. You change into cotton scrubs (no synthetic fabrics, no skin lotions, no jewellery), enter the chamber, and lie down (in a monoplace) or sit in a recliner (in a multiplace with multiple patients). Pressurisation takes five to ten minutes and feels like an aircraft descent. The 90-minute treatment phase is on 100 percent oxygen at 2.0 ATA, with three scheduled five-minute air-breaks. Decompression takes another five to ten minutes. Total time on-site is typically two and a half to three hours per visit including check-in.

Response is typically gradual rather than sudden. Most responders report some improvement in cognitive symptoms or fatigue by sessions 15 to 25, with the strongest gains in the second half of the course. A subset of patients experience a transient symptom flare in the first one to two weeks, followed by improvement; this is described in the published trial reports and is generally not a reason to discontinue. Side effects are usually limited to ear barotrauma during pressurisation (managed with pressure-equalisation techniques), temporary near-sightedness during the course (usually resolves within a few weeks of stopping), and mild fatigue.

Accessing HBOT for Long COVID in Canada

Long COVID is not on Ontario's OHIP-funded list for hyperbaric oxygen therapy (Ontario Schedule of Benefits, as of April 1, 2026); in other provinces, check with the provincial hospital programme. OHIP does not fund HBOT for long COVID in Ontario (Ontario Schedule of Benefits, as of April 1, 2026); in another province, check with your provincial hospital programme.

Patients seeking HBOT for long COVID are limited to private clinics on a self-pay basis. Each clinic sets its own price; clinics that publish prices online list $150 to $365 for a single session for one person (checked October 2026), so ask the clinic for a quote for the full course. Several Canadian private clinics actively offer HBOT for long COVID and have published clinical experience, including major hyperbaric centres in Toronto, Vancouver, Calgary, and Edmonton. The Canada Hyperbarics directory at canadahyperbarics.ca/facilities/ lists private clinics across Canada.

Some extended health insurance plans cover specific HBOT indications when accompanied by a physician referral. Long COVID is rarely listed as a covered indication on the standard Canadian extended-health benefit schedules, but coverage may be available through specific employer plans or private medical packages. Patients should confirm coverage details with their plan administrator before committing to a course.

A 2022 review by CADTH (the Canadian Agency for Drugs and Technologies in Health, now Canada's Drug Agency / CDA-AMC since May 2024) identified HBOT as an emerging therapy for post-COVID condition. Full Canadian guideline endorsement has not occurred, and Canadian regulators have not issued specific clinical guidance for long COVID HBOT to date.

Two Canadian-led trials of HBOT for long COVID are registered in Toronto: NCT06082518 (a randomised sham-controlled trial of HBOT in adults with persistent post-COVID symptoms) and NCT06452095 (a parallel investigation focused on cognitive and fatigue outcomes); check each listing for its current recruitment status. Eligible patients can self-refer or be referred by their family physician through ClinicalTrials.gov registration. Trial participation provides access to HBOT in this indication and contributes to the Canadian evidence base.

Discuss with a qualified healthcare professional. Then: Review Coverage Guide View Recognised Conditions

Provincial Access for Long COVID

Long COVID is not among the 15 indications OHIP insures in Ontario (Ontario Schedule of Benefits, as of April 1, 2026), nor on the Health Canada list of conditions it has licensed hyperbaric chambers to treat. Other provinces set their own lists; confirm coverage with the provincial hospital programme. The Ottawa Hospital, for one, states that it does not treat off-label or self-pay conditions. Patients seeking HBOT for Long COVID are limited to private clinics on a self-pay basis, or to enrolment in a Canadian recruiting trial. Use the links below for province-specific context.

ON Ontario

Hospital + Private

OHIP (Ontario Health Insurance Plan)
BC British Columbia

Hospital-Based

MSP (Medical Services Plan)
AB Alberta

Hospital + Private

Alberta Health / AHCIP
QC Quebec

Hospital-Based

RAMQ
SK Saskatchewan

Open for Outpatient Care

Saskatchewan Health Authority
MB Manitoba

CUHMA Lists No Unit

Manitoba Health
NS Nova Scotia

Hospital-Based

MSI (Medical Services Insurance)
NB New Brunswick

CUHMA Lists No Unit

Medicare NB
NL Newfoundland and Labrador

Hospital-Based

MCP (Medical Care Plan)
PE Prince Edward Island

CUHMA Lists No Unit

PEI Medicare
YT Yukon

CUHMA Lists No Unit

Yukon Health and Social Services
NT Northwest Territories

CUHMA Lists No Unit

NWT Health and Social Services
NU Nunavut

CUHMA Lists No Unit

Nunavut Department of Health

For acute or emergency presentations of Long COVID, call 911 first (in Nunavut, which has no 9-1-1 service, dial the first three digits of your local RCMP phone line followed by 1111, or 1-867-979-1111). In Ontario, hospital-based physicians can reach CritiCall Ontario at 1-800-668-4357. For a dive accident or injury, call 911 first (in Nunavut, which has no 9-1-1 service, your community RCMP line), then the Divers Alert Network (DAN) at +1 (919) 684-9111.

Risks and Contraindications

The only absolute contraindication to HBOT is untreated pneumothorax (because trapped intrathoracic air expands on decompression and can cause tension pneumothorax). Concurrent bleomycin chemotherapy (because hyperbaric oxygen can trigger or accelerate oxygen-induced pulmonary fibrosis) and concurrent disulfiram (because it inhibits superoxide dismutase, the enzyme that neutralises hyperbaric-oxygen-generated free radicals) are relative contraindications, weighed case by case. Prior bleomycin exposure with documented pulmonary clearance is a relative contraindication that requires individualised pulmonary-function review before HBOT. Relative contraindications include severe chronic obstructive pulmonary disease with bullous lung disease, uncontrolled seizure disorder, claustrophobia (manageable in monoplace chambers), recent middle-ear or sinus surgery, and uncontrolled hypertension. For long COVID specifically, severe post-exertional malaise warrants careful session pacing because the travel to and from the clinic and the cumulative effect of daily attendance can themselves trigger crashes; many Canadian clinics build flexibility into the schedule for PEM-prone patients. Patients with active cardiac arrhythmia or uncontrolled POTS require medical clearance and an autonomic assessment before starting the course.

Frequently Asked Questions

Emerging RCT evidence is encouraging, particularly for cognitive symptoms (brain fog, executive function) and fatigue. The 2022 Zilberman-Itskovich RCT (Scientific Reports, 73 patients, Shamir Medical Center) showed statistically significant improvements in global cognitive function, attention, executive function, energy, sleep quality, psychiatric symptoms, and pain interference after 40 HBOT sessions. The dedicated MRI substudy (Catalogna et al, Neuroimage Clinical 2022, same cohort) demonstrated functional and structural connectivity changes on resting-state fMRI and DTI, supporting the mechanistic basis. The Hadanny et al. one-year follow-up (Scientific Reports 2024) showed clinical benefits persisted at long-term assessment. The evidence base remains smaller than for the recognised hyperbaric indications, and individual response varies. Two Canadian trials are registered in Toronto (NCT06082518 and NCT06452095); check each listing for its current recruitment status.

Long COVID is not on Ontario's OHIP-funded list for HBOT (Ontario Schedule of Benefits, as of April 1, 2026), and no other province's list has been verified; check with the provincial hospital programme. OHIP does not fund it in Ontario (Ontario Schedule of Benefits, as of April 1, 2026); in another province, check with your provincial hospital programme. Another pathway is enrolment in a Canadian clinical trial in Toronto, where one is open to enrolment. Treatment outside of trials is on a self-pay basis at private clinics. Some extended health insurance plans cover specific HBOT indications; long COVID is rarely listed but worth confirming with your plan administrator.

Private clinics set their own prices. Clinics that publish prices online list $150 to $365 for a single session for one person (checked October 2026); ask the clinic for a quote for the full course. Confirm directly with the clinic before committing.

Course length is set by the treating team. In the 2022 Shamir Medical Center RCT (Zilberman-Itskovich et al), patients received 40 daily sessions.

Cognitive symptoms (brain fog, attention, executive function) and fatigue show the strongest signal in the published RCT evidence and have the most consistent improvement across patients in the Shamir Medical Center cohorts. Sleep quality and psychiatric symptoms also improve in trials. Autonomic symptoms (POTS, orthostatic intolerance) and exertional intolerance show smaller effect sizes and more variable individual response. Patients with predominantly cognitive or fatigue presentations are the best-supported candidates for a course based on current evidence.

Yes, this is a real risk. The travel to and from the clinic and the cumulative effect of daily HBOT attendance can themselves trigger PEM crashes in patients with significant post-exertional symptom exacerbation. A subset of patients experience a transient symptom flare in the first one to two weeks of the course before improving. Many Canadian clinics build pacing flexibility into the schedule (rest days, on-site recovery time, flexible attendance during flare periods) for PEM-prone patients. Discuss your PEM pattern with the treating clinic before committing to a course.

This is a decision for you and your healthcare team. Emerging evidence is encouraging but limited; cost is significant (a full course, paid by the patient) and long COVID is not on the Ontario OHIP-funded list for HBOT (elsewhere, check with your provincial hospital programme); individual response varies; and the demanding session schedule (the 2022 Shamir RCT used 40 daily sessions) may itself worsen symptoms in PEM-prone patients before improving. Before paying out-of-pocket, consider whether you would qualify for a Canadian trial in Toronto (NCT06082518 or NCT06452095; check each listing for its current recruitment status). Discuss with your physician whether HBOT fits your overall long COVID care plan.

Yes. Two Canadian-led trials are registered in Toronto: NCT06082518 (a randomised sham-controlled trial of HBOT in adults with persistent post-COVID symptoms) and NCT06452095 (a parallel investigation focused on cognitive and fatigue outcomes); check each listing for its current recruitment status. Eligible patients can self-refer or be referred by their family physician through ClinicalTrials.gov registration. Trial participation provides access to HBOT in this indication and contributes to the Canadian evidence base. Search the trial NCT IDs at clinicaltrials.gov for current eligibility criteria, contact information, and enrolment status.

You change into cotton scrubs, enter the chamber, and lie down (in a monoplace) or sit in a recliner (in a multiplace with multiple patients). Pressurisation takes five to ten minutes and feels like the descent in an aircraft. Most people clear their ears with the same technique used in flying. During the 90-minute treatment phase you breathe pure oxygen at 2.0 ATA, with three scheduled five-minute air-breaks. Decompression takes another five to ten minutes. The most common sensation during a session is a feeling of warmth and quiet. Total time on-site is typically two and a half to three hours per visit.

Last reviewed: April 28, 2026 | Reviewed by: Canada Hyperbarics Editorial Team | Editorial process | Research sources | Counts & methodology

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