Long COVID and HBOT: Why Hyperbaric Oxygen Therapy Delivers Measurable Improvement

You recovered from COVID-19 months ago. The acute infection is over. But the fatigue remains. The brain fog remains. Exercise intolerance worsens. Your doctor says You need time. But it has been months. Or a year. Or longer. Long COVID is not a matter of resting it off — it is a cascade of mitochondrial damage, neuroinflammation and autonomic dysfunction that requires active treatment.

What Long COVID Does to Your Mitochondria and Nervous System

SARS-CoV-2 is not the kind of virus that comes and goes. In a substantial proportion of those infected — estimates range from 10% to 30% — viral fragments remain in tissue: in the central nervous system, in endothelial cells of blood vessels, in the intestinal epithelium. These fragments are no longer infectious, but they keep the immune system in a state of chronic activation.

Long COVID recovery is complicated by the fact that conventional medicine has no treatment that addresses the underlying mechanisms. Rehabilitation programs focus on symptom management — pacing, cognitive behavioral therapy, gradual building. These approaches are not wrong, but they do not reach the level where the damage lies. The consequences play out on three levels.

Mitochondrial damage. SARS-CoV-2 interacts directly with mitochondrial proteins and disrupts the electron transport chain. The result: reduced ATP production in neurons and endothelial cells — precisely the cells that drive cognitive function and blood flow. This explains the chronic fatigue and brain fog that Long COVID patients describe.

Neuroinflammation. Microglial cells — the immune cells of the brain — remain activated by viral fragments and autoimmune responses. This chronic neuroinflammation disrupts neurotransmitter balance, inhibits neurogenesis and reduces synaptic plasticity. The cognitive effect is comparable to what is seen in brain fog from other causes, but the viral trigger makes the mechanism more persistent.

Autonomic dysfunction. Many Long COVID patients develop symptoms resembling postural orthostatic tachycardia syndrome (POTS): dizziness upon standing, heart palpitations, exercise intolerance. The cause is autoimmune-mediated damage to autonomic nerves, particularly the vagus nerve. When vagal tone decreases, the autonomic nervous system shifts toward sympathetic dominance — the body remains permanently in alarm mode, which blocks energetic recovery.

The Clinical Evidence: The Israeli RCT and Dutch Experiences

The strongest evidence for HBOT in Long COVID comes from the study by Zilberman-Itskovich et al. (2022), published in Nature Scientific Reports. This was a double-blind, placebo-controlled, randomized trial — the gold standard in clinical evidence.

Study design. 73 Long COVID patients, randomly divided between HBOT group (2.0 ATA, 100% oxygen) and sham group (1.0 ATA, regular air). 40 sessions of 90 minutes each, 5 times per week. Measurements before and after: neurocognitive testing, questionnaires, MRI perfusion scan.

Results. The HBOT group showed statistically significant improvements in: concentration and attention, memory, sleep quality. Additionally significant decrease in: fatigue, pain, depressive symptoms. The MRI perfusion scan showed increased cerebral blood flow in memory and executive function regions — evidence that the changes were not subjective but neurologically measurable.

Catalogna et al. (2022) confirmed in a follow-up study that HBOT specifically improves cerebral perfusion in the brain regions affected by Long COVID. The changes correlated with cognitive improvements — the greater the perfusion improvement, the stronger the cognitive recovery.

In the Netherlands, the MCHZ (Medical Center Hyperbaric Oxygen) in Goes has treated more than 100 Long COVID patients with results that confirm the Israeli data. The RECLAIM trial — a Dutch multicenter RCT — has been running since 2024 and will further strengthen the evidence base. The Dutch Society for Hyperbaric Medicine has permitted off-label treatment with HBOT for Long COVID since 2022.

The political and societal landscape is shifting. The Dutch parliament debate on Long COVID in January 2026 explicitly recognized that there is a treatment gap. It is no longer a question of whether HBOT works in Long COVID — the double-blind RCT data are clear on that. The question is when reimbursement follows. Until then, it is up to patients to make their own assessment — and that assessment begins with knowing the evidence.

It is also relevant to know what HBOT does not do. It is not a panacea and it does not guarantee complete recovery for every patient. The Israeli study showed significant improvement, not complete cure. Response varies: some patients experience noticeable improvement after just 10-15 sessions, others need the full protocol of 40 sessions. The duration of complaints, the severity of the initial infection and the extent of mitochondrial damage influence the outcome.

Hyperbaric Oxygen Therapy in Long COVID: How It Works

HBOT addresses the Long COVID cascade via five mechanisms that reinforce each other.

Hyperoxidation. Under elevated pressure, 10-15× more oxygen dissolves in blood plasma than under normal conditions. This dissolved oxygen reaches ischemic brain regions that red blood cells can no longer adequately reach — precisely the regions damaged by endothelial damage in Long COVID.

Anti-inflammatory action. HBOT modulates NF-κB signaling pathways and inhibits the production of pro-inflammatory cytokines. This breaks the chronic neuroinflammation that keeps microglial cells in an activated state.

Mitochondrial biogenesis. HBOT stimulates the production of new, functional mitochondria via PGC-1α activation. This compensates for the mitochondrial damage caused by SARS-CoV-2.

Stem cell mobilization. Thom et al. (2006) demonstrated that HBOT mobilizes CD34+ stem cells from bone marrow to peripheral circulation. These stem cells contribute to the regeneration of damaged endothelium and nerve tissue.

Angiogenesis. HBOT stimulates the formation of new blood vessels in ischemic regions, which improves blood flow structurally — not only temporarily, but through structural vascular remodeling that persists after the protocol ends.

These five mechanisms work synergistically: hyperoxidation provides the fuel, anti-inflammatory action creates the conditions, mitochondrial biogenesis builds energy capacity, stem cell mobilization repairs tissue damage, and angiogenesis provides structural blood flow improvement. It is this combination that explains why HBOT is more effective in Long COVID than interventions that address only a single mechanism.

Why The NEST Protocol Differs From Standard HBOT

NEST operates at 2.4 ATA — higher than the 1.5-2.0 ATA that most HBOT centers in the Netherlands use. Higher pressure means more dissolved oxygen and stronger activation of the mechanisms mentioned. This is relevant in Long COVID because the endothelial damage and neuroinflammation require a higher oxygen concentration to reach the target tissues.

But the main difference is the combination. HBOT alone addresses oxygen delivery and inflammation. At NEST we add two interventions that tackle the other aspects of the Long COVID cascade.

Photobiomodulation (PBM, 660/850nm) activates cytochrome-c-oxidase in the mitochondria that HBOT has newly created and existing mitochondria that HBOT has reached with extra oxygen. PBM optimizes the use of that oxygen — it is the difference between providing fuel and tuning the engine.

Vagal nerve therapy (VAT, 40Hz) addresses the autonomic dysfunction that is central to Long COVID. By raising vagal tone and activating the parasympathetic nervous system, sympathetic overdrive is broken. For patients with POTS-like symptoms, this is an essential part of the protocol.

The result is an integrated protocol that addresses the three pillars of Long COVID pathology simultaneously: mitochondrial damage (HBOT + PBM), neuroinflammation (HBOT), autonomic dysfunction (VAT).

Costs, Reimbursement and Practical Information

Transparency about costs is part of the NEST protocol.

HBOT for Long COVID is not covered by the basic health insurance package. This applies to all HBOT centers in the Netherlands for this indication. However, HBOT is tax-deductible as specific healthcare costs through the Tax Authority, provided it is supported by a medical indication.

A referral from Your doctor or specialist is recommended but not required. NEST operates on the basis of direct access — Your intake begins via WhatsApp or telephone contact. During the intake Your specific situation is assessed: symptom pattern, duration, previous treatments, and expectation management.

Our reviews and experiences give a picture of what Long COVID patients have experienced at NEST. We do not publish promises — we publish measurable outcomes and personal experiences.

What You can expect. The NEST Long COVID protocol typically consists of 20-40 HBOT sessions combined with PBM and VAT. The frequency is 3-5 sessions per week. Intermediate evaluations after 10 and 20 sessions determine whether the protocol is adjusted. Most patients report first improvements in cognitive clarity and sleep quality after 8-12 sessions. Energy level and exercise tolerance typically improve later in the course. After completion of the intensive protocol, the Bio-Balance Membership offers maintenance treatments to maintain the level achieved.

Long COVID is not a matter of patience and waiting. It is an active cascade of mitochondrial damage, neuroinflammation and autonomic dysfunction that can persist without intervention. The clinical evidence — double-blind, placebo-controlled — shows that HBOT measurably breaks this cascade. At NEST we combine HBOT at 2.4 ATA with PBM and vagal nerve stimulation because Long COVID is not one problem but three. Your recovery begins with the Burnout Neuro Recovery Retreat — the protocol that addresses all three.