What hyperbaric oxygen therapy is and how it works

Hyperbaric oxygen therapy (HBOT) is a medical treatment where you breathe pure oxygen inside a pressurized chamber. The chamber increases air pressure to two to three times normal atmospheric pressure. At this higher pressure, your lungs absorb more oxygen than they would at sea level, and that oxygen dissolves into your bloodstream and body tissues more efficiently.

A typical session lasts 60 to 120 minutes. You enter a clear acrylic chamber (either alone in a monoplace chamber or with others in a multiplace chamber where oxygen is delivered through a mask or hood), breathe the oxygen, and the pressure gradually increases and then decreases. Most people undergoing HBOT have multiple sessions—often 20 to 40 treatments over several weeks—rather than a single visit.

The theory behind HBOT is straightforward: tissues that are injured, infected, or not getting enough blood flow need oxygen to heal. By flooding your body with oxygen under pressure, the therapy aims to help those tissues repair themselves and reduce inflammation.

Key Takeaways

  • Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized chamber to increase oxygen absorption in your blood and tissues.
  • The therapy is FDA-approved for specific medical conditions like diabetic foot ulcers, carbon monoxide poisoning, and non-healing wounds, but evidence for other uses is still developing.
  • Sessions typically last one to two hours and most treatment plans involve multiple visits over weeks or months.
  • Side effects are usually mild—ear discomfort and sinus pressure are most common—but serious complications are rare when the chamber is properly maintained.
  • Cost varies widely depending on whether your treatment is covered by insurance and whether you are being treated at a hospital or private clinic.

Conditions where HBOT has established medical support

The U.S. Food and Drug Administration (FDA) has approved hyperbaric oxygen therapy for a defined list of conditions. These include diabetic foot ulcers that are not healing with standard wound care, carbon monoxide poisoning, decompression sickness (the "bends" in divers), severe infections of bone or soft tissue, non-healing wounds from radiation therapy, and certain types of anemia.

For these conditions, HBOT is considered a standard medical treatment, and insurance is more likely to cover it. The evidence supporting its use in these areas comes from clinical trials and decades of medical practice, particularly in wound care and emergency medicine.

Outside this FDA-approved list, people sometimes pursue HBOT for conditions like autism, cerebral palsy, fibromyalgia, Lyme disease, and chronic fatigue syndrome. The scientific evidence for these uses is much thinner—some small studies suggest possible benefit, but larger, well-designed trials have not confirmed whether the therapy actually works for these conditions. If you are considering HBOT for something not on the FDA list, understanding the current state of evidence matters before you commit time and money.

What the research actually shows

For FDA-approved uses, the evidence is solid. Diabetic foot ulcers, for example, have been studied extensively, and HBOT has been shown to reduce the need for amputation and speed healing when combined with standard wound care. Carbon monoxide poisoning and decompression sickness are emergencies where HBOT is life-saving or prevents permanent disability.

For other conditions, the picture is less clear. Some studies show modest improvements in pain, function, or healing, but many of these studies are small, lack a control group, or cannot rule out placebo effect. A reader looking at research on HBOT for autism or chronic pain, for instance, will find conflicting results and disagreement among researchers about whether the therapy works at all.

This does not mean HBOT is ineffective for these conditions—it means the evidence is not yet strong enough for doctors to recommend it as standard treatment. If you are considering HBOT for a condition not on the FDA list, it is worth asking your doctor what the current evidence says and whether they think it is worth trying in your specific situation.

What to expect during treatment and possible side effects

Before your first session, you will have a medical evaluation to make sure HBOT is safe for you. The technician will explain how the chamber works and what you will feel. As the pressure increases, you may feel ear or sinus pressure similar to what you experience on an airplane—most people manage this by yawning, swallowing, or using techniques the technician teaches you.

During the session, you breathe oxygen and relax. Some people read, others sleep. The most common side effect is barotrauma—pressure-related discomfort in your ears or sinuses—which usually goes away once you learn equalization techniques. Temporary blurred vision, fatigue, and mild headache can occur but typically resolve between sessions.

Serious side effects are rare when equipment is properly maintained and you are screened beforehand. Oxygen toxicity (a condition from breathing too much oxygen under pressure) is prevented by following strict protocols about session length and frequency. Claustrophobia can be an issue for some people, though multiplace chambers are larger and less confining than monoplace ones.

Cost and insurance coverage

The cost of hyperbaric oxygen therapy varies significantly depending on where you receive it and whether insurance covers your treatment. Hospital-based HBOT programs typically charge between $1,500 and $3,000 per session, though the actual cost to you depends on your insurance plan and deductible. Private clinics may charge less per session but often require upfront payment.

Insurance coverage depends on your diagnosis. If you are being treated for an FDA-approved condition, your insurance is likely to cover at least part of the cost. If you are pursuing HBOT for a condition not on the FDA list, coverage is unlikely, and you would pay out of pocket.

Before starting treatment, ask the clinic or hospital for a cost estimate and contact your insurance company to confirm what they will cover. Some facilities offer payment plans if you are paying privately. The total cost of a full treatment course (often 20 to 40 sessions) can range from $30,000 to $120,000 or more, depending on frequency and location.

How HBOT differs from other oxygen therapies

Hyperbaric oxygen therapy is different from supplemental oxygen therapy, which you may receive at home or in a hospital if you have a chronic lung condition. Supplemental oxygen increases the amount of oxygen you breathe but does not increase pressure. HBOT's pressure is what allows oxygen to dissolve into your blood and tissues at much higher concentrations.

Topical oxygen therapy—where oxygen is applied directly to a wound—is another option for some non-healing wounds. It is less invasive than HBOT but also less studied. Ozone therapy and other oxygen-based alternative treatments exist but operate on different principles and have different evidence bases.

If you are exploring oxygen-based treatments, your doctor can help you understand which approach makes sense for your specific condition and what the evidence supports.

Questions to ask before starting treatment

If you are considering hyperbaric oxygen therapy, it helps to go in with specific questions. Ask your doctor whether HBOT is standard treatment for your condition or whether it is still experimental. Ask what the evidence shows for your particular diagnosis and what success looks like—is the goal to heal a wound, reduce pain, or something else?

Ask the clinic how many sessions they recommend, how long each session lasts, and what the total time commitment is. Ask about their safety record, how often equipment is maintained, and what side effects you should watch for. Ask whether they have treated other patients with your condition and what results they have seen.

Finally, ask about cost upfront and confirm with your insurance whether your treatment will be covered. A clinic that is transparent about these details and willing to answer your questions is a good sign.

Frequently Asked Questions

Is hyperbaric oxygen therapy the same as breathing oxygen at home?

No. Home oxygen therapy delivers extra oxygen at normal air pressure. HBOT pressurizes the chamber to two to three times normal pressure, which allows your lungs to absorb much more oxygen and your blood to carry it to tissues more effectively. The pressure is what makes HBOT different and what the therapy relies on to work.

Can I use HBOT to treat a condition my doctor has not mentioned?

You can explore it, but understand the evidence first. If your condition is not on the FDA-approved list, the research supporting HBOT for your diagnosis may be limited or conflicting. Talk to your doctor about what the current evidence shows and whether they think it is worth trying. Insurance is unlikely to cover off-label uses, so cost will be your responsibility.

What happens if I feel claustrophobic in the chamber?

Tell the technician before your session starts. Monoplace chambers (single-person) are smaller and can feel confining, but multiplace chambers are larger and allow you to bring a companion. Some facilities can adjust your treatment plan or use techniques to help you feel more comfortable. Claustrophobia is manageable but worth discussing upfront.

How long does it take to see results from HBOT?

This depends on your condition and what you are hoping to see improve. For wounds, some people notice changes within a few sessions, while others need weeks of treatment. For other conditions, results may be subtle or take longer to appear. Ask your doctor what timeline is realistic for your diagnosis and what signs of improvement to watch for.

Are there any conditions that make HBOT unsafe?

Certain medical conditions and medications can increase your risk of side effects. Fever, untreated claustrophobia, and a history of lung collapse are examples. Your medical evaluation before treatment will screen for these. Be honest with your doctor about your full medical history so they can determine whether HBOT is safe for you.