Hyperbaric Chamber for Fibromyalgia: Does HBOT Relieve Chronic Pain?

hyperbaric oxygen therapy (HBOT) is one of the more promising emerging treatments for fibromyalgia, with clinical research showing it can reduce pain, improve cognitive function, and normalize abnormal brain activity patterns in fibromyalgia patients. The strongest evidence comes from a 2015 randomized controlled trial that demonstrated significant improvements after 40 sessions at 2.0 ATA, with SPECT imaging confirming measurable changes in brain regions involved in pain processing. This is something we explore further in our treatment costs. It is one of several range of chronic conditions explored with hyperbaric oxygen that researchers are actively investigating. It is part of a broader group of HBOT for pain conditions that are being studied in hyperbaric research.

How Does HBOT Work for Fibromyalgia?

Fibromyalgia is increasingly understood as a disorder of central pain processing rather than a problem with peripheral tissues. Research suggests that neuroinflammation, abnormal brain perfusion patterns, and mitochondrial dysfunction all play roles in driving the widespread pain, fatigue, and cognitive difficulties that define the condition. Want the details? Read our alternatives to HBOT. HBOT targets several of these underlying mechanisms simultaneously:

Reduced Neuroinflammation

Breathing 100% oxygen at elevated pressure has well-documented anti-inflammatory effects throughout the body, including the central nervous system. In fibromyalgia patients, chronic low-grade neuroinflammation is thought to sensitize pain pathways and contribute to symptoms like brain fog and fatigue. HBOT reduces pro-inflammatory cytokines and promotes the resolution of inflammation in neural tissue.

Brain Perfusion and SPECT Normalization

SPECT imaging studies have consistently shown that fibromyalgia patients have abnormal blood flow patterns in brain regions responsible for pain processing. HBOT increases oxygen delivery to these hypoperfused areas, and research has demonstrated that repeated sessions can normalize SPECT findings in regions including the posterior cortex, hippocampus, and frontal areas.

Pain Processing Modulation

Central sensitization, where the nervous system amplifies pain signals, is a hallmark of fibromyalgia. HBOT appears to reduce this sensitization by promoting neuroplasticity and helping recalibrate overactive pain circuits. The result is a higher pain threshold and reduced perception of widespread pain.

HBOT led to significant improvement in all fibromyalgia symptoms and rectified abnormal brain activity patterns visible on SPECT imaging.”
Efrati et al., PLoS ONE, 2015

Mitochondrial Support

Emerging research links fibromyalgia to impaired mitochondrial function in both muscle tissue and neural cells. The elevated oxygen levels achieved during HBOT sessions support mitochondrial repair and biogenesis, potentially addressing the cellular energy deficits that contribute to fatigue and muscle pain. For a broader look at the science, visit our HBOT research overview.

The Key Study: Efrati 2015

The most significant evidence for HBOT in fibromyalgia comes from a randomized controlled trial published in PLOS ONE in 2015¹, led by Dr. Shai Efrati at Tel Aviv University’s Sagol Center for Hyperbaric Medicine and Research. Curious about this? Our 2015 study in PLOS ONE showing HBOT reduced fibromyalgia symptoms has the full picture.

Study Design

The trial enrolled 48 women diagnosed with fibromyalgia for at least two years. Participants were randomly assigned to one of two groups: a treatment group that received HBOT immediately, and a crossover control group that received HBOT after a two-month delay. This crossover design allowed every participant to eventually receive treatment while still maintaining a proper control comparison.

The HBOT protocol consisted of 40 sessions at 2.0 ATA (atmospheres absolute), with each session lasting 90 minutes and including five-minute air breaks. Sessions were conducted five days per week over a period of eight weeks.

Results

The findings were striking. Compared to the control period, women who received HBOT showed:

• Significant reduction in pain as measured by tender point counts and pain threshold testing
• Improved quality of life scores across physical function, general health, vitality, and social functioning domains on the SF-36 questionnaire
• Reduced fibromyalgia symptom severity on the Fibromyalgia Impact Questionnaire
• Normalized brain SPECT imaging showing corrected activity in brain areas associated with pain processing, including regions previously showing abnormal hyperactivity or reduced perfusion

Importantly, the crossover group showed similar improvements once they began their own HBOT course, reinforcing the consistency of the results. The SPECT imaging data was particularly valuable because it provided objective biological evidence of change, not just self-reported symptom improvement.

Limitations

The study was relatively small at 48 participants, and the sample was limited to women. The crossover design, while useful, meant the control group only waited two months before receiving treatment, making long-term placebo comparison impossible. The researchers also acknowledged that blinding was not feasible since participants knew whether they were in a pressurized chamber.

Additional Research

Several other studies have investigated HBOT for fibromyalgia, though none match the Efrati trial in scale or design quality. A 2004 pilot study by Yildiz and colleagues treated 26 fibromyalgia patients² with 15 sessions of HBOT at 2.4 ATA. They reported improvements in pain thresholds at tender points, though the effects were modest and the study lacked a control group.

A follow-up study from the Efrati group, published in 2018, examined the long-term durability of HBOT benefits. The researchers found that many patients maintained improvements at follow-up, though some experienced gradual symptom return and benefited from maintenance sessions.

A 2022 systematic review examining HBOT for chronic pain conditions, including fibromyalgia, concluded that the evidence is promising but still limited by small sample sizes. The reviewers called for larger, multi-center trials to confirm the findings.

Across multiple clinical studies, HBOT achieved pain relief rates of 87.5% to 100% in fibromyalgia patients, with improvements observed as early as 10 sessions.”
Fang et al., Frontiers in Medicine, 2025

It is worth being honest about where things stand: the evidence base is encouraging but not yet robust enough for HBOT to be considered a standard fibromyalgia treatment. Most of the positive data traces back to one research group, and independent replication at scale has not yet been published.

Treatment Protocols

Most clinics offering HBOT for fibromyalgia base their approach on the Efrati 2015 protocol: For a deeper dive, check out our Mayo Clinic fibromyalgia overview.

• Pressure: 2.0 ATA (atmospheres absolute)
• Session length: 90 minutes of oxygen breathing time, with periodic air breaks
• Frequency: Five sessions per week
• Total sessions: 40 sessions over approximately eight weeks
• Chamber type: Monoplace or multiplace hard-shell chambers (soft-shell chambers cannot reach 2.0 ATA)

The five-day-per-week schedule is important. The Efrati study was designed around consecutive daily sessions to maintain consistent oxygen saturation and promote cumulative neuroplastic changes. Spacing sessions further apart (two or three times per week) has not been studied for fibromyalgia specifically, and it is unclear whether a less intensive schedule would produce the same results.

Some patients pursue maintenance sessions after the initial 40-session course, typically one to two sessions per week, to sustain improvements. Your provider can help determine whether maintenance is appropriate. For a detailed breakdown of what sessions involve, see our guide to HBOT sessions.

Be aware that HBOT is not covered by HBOT insurance for fibromyalgia. You can learn more about HBOT insurance coverage for other approved conditions.

What Results to Expect

Based on available research and clinical reports, here is a realistic timeline of what fibromyalgia patients may experience with HBOT:

Sessions 1 to 15

Most patients do not notice dramatic changes in the first two to three weeks. Some report mild improvements in sleep quality and a subtle reduction in brain fog. Temporary fatigue after sessions is common during this early phase as the body adjusts to increased oxygen exposure. Learn more about potential HBOT side effects.

Sessions 15 to 30

This is where most patients in the Efrati study began experiencing noticeable improvements. Pain levels may start to decrease, energy often improves, and cognitive clarity tends to sharpen. The changes are typically gradual rather than sudden.

Sessions 30 to 40

The final stretch of the protocol is where cumulative benefits tend to consolidate. Pain reduction becomes more consistent, and quality-of-life improvements are most apparent. Not every patient responds to the same degree. The Efrati study showed statistically significant group-level improvements, but individual responses varied.

After Treatment

Some patients maintain improvements for months after completing the 40-session course. Others experience a gradual return of symptoms over weeks to months. Maintenance sessions may help sustain benefits for those who respond well initially. For more on this, read our article on how long HBOT effects last.

It is important to set realistic expectations. HBOT is not a cure for fibromyalgia. The goal is meaningful symptom reduction and improved quality of life, not complete remission. Patients who respond well often still benefit from continuing their existing fibromyalgia management strategies alongside HBOT.

Who Should Not Try HBOT

HBOT is generally safe when administered by trained professionals, but it is not appropriate for everyone. Discuss your full medical history with your provider before starting treatment.

Absolute Contraindications

HBOT should not be used if you have:

• Untreated pneumothorax (collapsed lung) – pressure changes can worsen this condition and become life-threatening
• Certain chemotherapy drugs – bleomycin, cisplatin, doxorubicin, and disulfiram may interact dangerously with high-oxygen environments

Relative Contraindications

Your provider may need to take extra precautions or postpone treatment if you have:

• Upper respiratory infection or sinus congestion – difficulty equalizing pressure can cause ear or sinus barotrauma
• Seizure disorder – high-pressure oxygen can lower seizure threshold in susceptible individuals
• Chronic obstructive pulmonary disease (COPD) – altered breathing drive may require modified protocols
• High fever – increases the risk of oxygen toxicity
• History of ear surgery or chronic ear problems – pressure equalization may be difficult or risky
• Claustrophobia – may require sedation or use of a multiplace chamber instead
• Pregnancy – insufficient safety data exists for routine use during pregnancy

Talk to Your Doctor First

Even if you do not have the conditions listed above, always consult your physician before starting HBOT, especially if you take insulin (blood sugar may drop during treatment), have a pacemaker or implanted device, or are currently taking any medications. For a full overview of HBOT side effects and risks, see our detailed guide.

References

1. Efrati S, et al.. “Hyperbaric Oxygen Therapy Can Diminish Fibromyalgia Syndrome.” PLoS ONE, 2015. DOI: 10.1371/journal.pone.0127012
2. Atzeni F, et al.. “Hyperbaric oxygen treatment of fibromyalgia: a prospective observational clinical study.” Clinical and Experimental Rheumatology, 2019. DOI: PMID 30747099
3. da Mota Neto J, et al.. “Protocol of HOTFy: randomised clinical trial to hyperbaric oxygen therapy in fibromyalgia.” BMJ Open, 2023. DOI: 10.1136/bmjopen-2022-069153
4. Fang J, et al.. “Hyperbaric oxygen therapy in rheumatic and autoimmune diseases: mechanisms and clinical evidence.” Frontiers in Medicine, 2025. DOI: 10.3389/fmed.2025.1706637
5. Curtis K, et al.. “Evaluation of a Hyperbaric Oxygen Therapy Intervention in Individuals with Fibromyalgia.” Pilot study, 2021.
6. Undersea and Hyperbaric Medical Society. “HBO Therapy Indications.” UHMS, 2024. DOI: uhms.org