What Is Hyperbaric Oxygen Therapy (HBOT)?

Also Known as Hyperbaric Chamber Treatment

Hyperbaric chamber therapy is a noninvasive medical treatment that boosts your body's oxygen levels. Known medically as hyperbaric oxygen therapy (HBOT), it treats carbon monoxide poisoning, decompression sickness, and slow-healing wounds.

HBOT involves sitting in a hyperbaric chamber—an enclosed space filled with high-pressure oxygen— and breathing. This allows your lungs to take in more oxygen, thereby increasing circulating oxygen in your bloodstream.

This article explores hyperbaric chamber therapy. It discusses how HBOT works and what it treats. It also explains the possible side effects of hyperbaric treatment and whether or not insurance covers it.

How to prepare for hyperbaric chamber treatment
 Verywell / Brianna Gilmartin

What Is a Hyperbaric Chamber?

A hyperbaric chamber is a high-pressurized, enclosed space filled with pure oxygen. There are two types of hyperbaric chambers:

  • Monoplace hyperbaric chambers: Clear acrylic tubes designed for one person to lie down or recline. High-pressure oxygen is delivered into the tube.
  • Multiplace hyperbaric chambers: A small pressurized room (similar to an airplane cabin) with multiple chairs. A mask or a lightweight, transparent hood placed over the head delivers high-pressure oxygen to each individual.

The air pressure inside a hyperbaric chamber is two or three times greater than in a typical room. This improves oxygen absorption and speeds healing.

What Does a Hyperbaric Chamber Feel Like?

Most people find a hyperbaric chamber to be pleasant and relaxing. The increased air pressure may feel like you are in a plane climbing to a higher altitude and cause your ears to pop. You may feel lightheaded or dizzy during treatment. Afterward, it is common to feel like you completed a cardio workout.

How Does Hyperbaric Oxygen Therapy Work?

Hyperbaric chamber therapy, also known as recompression therapy, works by providing a controlled stream of oxygen, an essential element for human life. Oxygen is absorbed by the lungs, where it enters the bloodstream, travels to the heart, then circulates to all of the tissues in your body.

HBOT delivers pure oxygen under high air pressure, which helps the body take in more healing oxygen. This, in turn, allows for higher oxygen concentrations in the blood and other body fluids. Oxygen-rich fluids travel through different organ systems, helping to repair damaged tissues.

For example, higher levels of oxygen in cerebral spinal fluid—the fluid that surrounds the brain and spinal column—may be helpful for regenerating neurons after a stroke. A greater concentration of oxygen in the lymphatic fluid may help to clear waste from lymph nodes and bolster your immune system.

How Long Is a Hyperbaric Therapy Session?

Each hyperbaric therapy session lasts about two hours. The number of treatments you may need depends on your condition. For example, carbon monoxide poisoning commonly requires one to three sessions.

Hyperbaric Chamber Benefits

Many injuries and illnesses result in a disruption of oxygen-rich blood, being able to travel to affected areas of the body. The body needs oxygen to heal itself. 

For example, diabetes can cause poor circulation, which makes it more difficult for oxygen-rich red blood cells to reach damaged tissue. This results in slow-to-heal injuries and wounds that are at high risk of infection.

HBOT helps to boost oxygen levels in your blood, which is believed to assist the body in the following ways:

  • Helps immune cells to kill bacteria
  • Reduces inflammation
  • Improves collateral circulation (the growth of new blood vessels that provide extra oxygen to affected tissues)

Hyperbaric oxygen therapy can be utilized as a stand-alone treatment or a procedure that can boost the action of medications, such as antibiotics.

Conditions Treated by Hyperbaric Oxygen Therapy

HBOT is used to treat many different medical conditions and injuries that benefit from increased oxygen levels in the tissues. 

Some of the common uses for hyperbaric oxygen therapy that are often covered by insurance include:

  • Arterial gas embolism (air bubbles in the blood vessels)
  • Carbon monoxide poisoning (from breathing noxious fumes)
  • Cyanide poisoning
  • Decompression sickness (a common scuba diving condition, also called "the bends")
  • Specific types of non-healing wounds, such as diabetic wounds
  • Gas gangrene (fast-spreading gangrene in infected wounds that gives off a foul-smelling gas)
  • Intracranial abscess (originating from an ear infection, sinus infection, or another primary source of infection)
  • Tissue damage from radiation therapy
  • Osteomyelitis (long-term inflammation of bone or bone marrow)
  • Compromised skin grafts or flaps
  • Severe anemia
  • Brain abscess
  • Burns
  • Crushing injury
  • Sudden deafness
  • Sudden, painless vision loss

Additional Conditions HBOT May Treat

Several other types of injuries and illnesses are said to benefit from HBOT. However, there is a lack of clinical evidence to back up many of these claims. Therefore, it is not usually covered by insurance when used to treat the following:

  • Lyme disease
  • Near drowning
  • Recovery from plastic surgery
  • Allergies
  • Alzheimer's disease
  • Arthritis
  • Asthma
  • Autism
  • Bell's palsy
  • Brain injury
  • Cancer
  • Cerebral palsy
  • Chronic fatigue syndrome
  • Cirrhosis
  • Depression
  • Fibromyalgia
  • Gastrointestinal ulcers
  • Heart disease
  • Heatstroke
  • Hepatitis
  • Migraine
  • Multiple sclerosis
  • Parkinson's disease
  • Spinal cord injury
  • Sports injuries
  • Stroke
  • Traumatic brain injury

Side Effects of Hyperbaric Oxygen Therapy

Although hyperbaric chamber treatment is considered a natural and relatively safe therapy mode, some side effects are involved. These are primarily due to changing air pressure and affect the ears, sinuses, and lungs.

Side effects of HBOT are usually mild and temporary and may include:

  • Ear pain or pressure
  • Ear popping
  • Fluid buildup in the middle ear
  • Lung collapse or barotrauma (rare)
  • Ruptured eardrum
  • Sinus pain or pressure
  • Temporary vision changes causing nearsightedness

To minimize problems with ears and sinuses, try yawning or swallowing to pop your ears and prevent pressure. Ear tubes are sometimes placed to reduce pressure during treatment.

Inhaling high concentrations of oxygen can also lead to oxygen toxicity, which can cause:

  • Fluid in the lungs
  • Lung failure
  • Seizures

Your healthcare provider will instruct you to take frequent breaks to breathe regular air to prevent oxygen poisoning.

Can Hyperbaric Oxygen Therapy Cause Heart Problems?

In general, heart problems are not considered a side effect of HBOT. However, there have been isolated reports of disturbances to electrical activity in the heart following hyperbaric chamber treatment. More research is needed before any clear link can be made.


Hyperbaric chamber therapy should not be used by people who have:

  • Lung conditions (due to the increased risk of a collapsed lung)
  • A cold
  • A fever
  • A recent ear surgery
  • A recent injury
  • Claustrophobia (fear of small spaces)


Hyperbaric chambers can be a fire hazard. Pure oxygen is highly flammable that is easily ignited by a spark. Cigarette lighters and battery-powered devices are not allowed in the treatment area.

How to Prepare for Hyperbaric Oxygen Therapy 

Before an HBOT session, it’s essential to shower. Avoid wearing perfumes, deodorants, petroleum-based skincare, and flammable haircare products like hair spray.

Do not drink alcohol or carbonated drinks for at least four hours before a session,

Smokers are encouraged to quit smoking when they receive therapy because tobacco products block the body’s natural ability to transport oxygen.

Your healthcare provider may ask the following questions before treatment:

  • Do you have any cold, nasal congestion, or flu symptoms?
  • Do you have a fever?
  • Are you pregnant?
  • Have you eaten before treatment?
  • If you have diabetes, did you take your insulin before treatment?
  • Has there been any recent change in your medications?
  • Do you have anxiety?

Once your session is completed, you should not have any restrictions or limitations on activity or diet, though you may be tired or dizzy afterward.

Research on Hyperbaric Oxygen Treatments

Clinical research studies on hyperbaric chambers have examined its safety and effectiveness for various maladies.

Skin Grafts and Flaps

One study examined the efficacy of HBOT used to treat tissue grafts and flaps. The findings concluded that HBOT can "increase the likelihood of composite graft survival, improve skin graft outcomes, and enhance flap survival."

The study authors also explain that HBOT is "not indicated for healthy, non-compromised tissue, but is a valuable salvage adjunct in the treatment of threatened grafts and flaps."

Traumatic Brain Injury

In human studies involving those with severe traumatic brain injury (TBI), HBOT was deemed a "promising, safe, therapeutic strategy for severe TBI patients." 

Note this does not mean that there is clear evidence that HBOT is effective for traumatic brain injuries—more research studies are needed in this area. 


In one United States Government Accountability Office report, three article reviews found that hyperbaric oxygen therapy was safe. 

Cerebral Palsy (CP)

Although HBOT has been touted as one of the most effective procedures for cerebral palsy, one double-blind placebo study (the gold standard of clinical research studies) discovered HBOT was no different than pressurized air for kids with CP.


According to Dan Rose, M.D., in an American Family Physician journal entry, "Hyperbaric oxygen therapy (HBOT) is associated with remission rates [a period during which symptoms of a disease are reduced or disappear] of 81% to 85% at two to three years in patients with chronic refractory osteomyelitis."

Chronic refractory osteomyelitis is an infection in the bone that lasts longer than six months (regardless of antibiotic therapy and other appropriate medical treatment).


Hyperbaric oxygen therapy helps to increase the amount of oxygen in your body. It involves sitting or lying down in a high-pressurized enclosure known as a hyperbaric chamber. A session takes about two hours. 

HBOT is used to treat carbon monoxide poisoning, severe burns, slow-healing wounds, and decompression sickness. It is also used in alternative medicine to treat neurological conditions, depression, and heart disease, though more research is needed to confirm its effectiveness. 

Hyperbaric chamber therapy is typically pleasant and relaxing, though air pressure changes can cause ear and sinus pressure. In rare cases, HBOT can cause a ruptured eardrum, collapsed lung, or oxygen poisoning. 

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Sherry Christiansen
Sherry Christiansen is a medical writer with a healthcare background. She has worked in the hospital setting and collaborated on Alzheimer's research.