Hyperbaric Oxygen Therapy in Diving Medicine

By Rubicon Foundation editorial team

5 min read · 9 November 2026

Hyperbaric oxygen therapy (HBOT) is the administration of oxygen at a pressure higher than the normal pressure at the surface, usually in a pressurised chamber. In diving medicine, it is best known as a treatment for decompression illness and arterial gas embolism, conditions in which bubbles can impair circulation or injure tissue. Understanding the therapy means understanding both oxygen biology and pressure.

What does hyperbaric oxygen do?

At increased pressure, more oxygen dissolves directly into the blood plasma, in addition to the oxygen carried by haemoglobin. This can increase oxygen delivery to tissues where blood flow is impaired. The treatment also reduces the volume of gas bubbles, while the chamber pressure is maintained.

These effects explain why HBOT is used in selected diving emergencies. Decompression sickness can occur when dissolved inert gas forms bubbles during or after ascent; arterial gas embolism occurs when gas enters the arterial circulation, often after lung overexpansion during ascent. The conditions differ, but both can require urgent assessment and recompression.

How is chamber treatment related to diving?

Recompression treatment recreates increased ambient pressure in a controlled chamber, then uses staged pressure reduction to manage the return to surface pressure. Oxygen is commonly breathed during parts of treatment, with air breaks used to limit oxygen exposure. The precise treatment schedule is a clinical decision, not a general-purpose recipe.

A diving emergency calls for prompt first aid and specialist care. A chamber treatment team considers the diver’s symptoms, dive history, examination and response over time. Some symptoms can improve and then return, so apparent early recovery does not remove the need for medical assessment.

Which concepts shape treatment?

Hyperbaric care depends on several linked variables. Pressure changes affect gas volume and gas exchange; oxygen concentration and exposure time affect both therapeutic benefit and toxicity risk. The diver’s condition and the timing of care also matter.

Ambient pressure: the pressure surrounding the patient inside the chamber.
Partial pressure: the share of total gas pressure attributable to oxygen or another gas.
Recompression: raising pressure in a controlled setting as part of treatment for diving-related bubble illness.
Oxygen toxicity: harmful effects that can follow excessive oxygen exposure, with risk influenced by pressure and duration.
Recompression schedule: a planned sequence of pressure and breathing-gas periods, selected for the clinical situation.

These concepts also connect HBOT with wider research into tissue oxygenation, gas bubbles, vascular injury and the body’s response to pressure. A chamber can deliver a controlled environment, but it does not make every pressure-related illness the same or guarantee the same clinical course.

What risks and practical limits matter?

Chamber treatment has risks as well as potential benefits. Pressure changes can cause ear or sinus barotrauma if spaces do not equalise; oxygen exposure can produce central nervous system or pulmonary toxicity. Clinicians manage these risks through patient assessment, control of exposure and monitoring during treatment.

HBOT is not a substitute for preventing diving injuries, and it is not appropriate for every illness. The decision to use it depends on the diagnosis, the patient’s condition and the available clinical setting. For suspected decompression illness or gas embolism, seek emergency care and consult a diving-medicine physician.

How does HBOT fit into diving medicine?

Hyperbaric oxygen therapy sits at the intersection of diving physiology and clinical medicine. Its use reflects a central feature of diving emergencies: pressure can alter the behaviour of gases in the body, while breathing oxygen under pressure can change tissue oxygen availability. Research in this area examines how those effects can be applied safely to specific conditions.

For divers and clinicians, the important distinction is between a treatment mechanism and a treatment decision. Knowing why recompression may help does not determine the correct schedule or replace diagnosis; those require trained clinical judgment and access to appropriate facilities.

Frequently asked questions

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

No. HBOT combines oxygen breathing with pressure above normal surface pressure. Pressure changes how gases behave and increases the amount of oxygen dissolved in plasma.

Why is recompression used for some diving injuries?

Increased pressure reduces bubble volume, and oxygen under pressure can support oxygen delivery to tissues. Treatment selection and pressure schedules require clinical assessment.

Can a diver decide independently whether chamber treatment is needed?

No. Suspected decompression illness or arterial gas embolism needs urgent medical evaluation. Contact emergency services and a diving-medicine physician rather than trying to assess the need for chamber treatment alone.

An original research-library explainer written by the Rubicon editors. It is not a summary of a specific publication.