Screening for Oxygen Sensitivity in Divers

By Rubicon Foundation editorial team

5 min read · 10 November 2026

Screening for oxygen sensitivity is the effort to identify whether people differ in their response to elevated oxygen pressure, especially during diving or hyperbaric exposure. The question matters because oxygen is essential yet can become toxic at increased partial pressures, making individual response relevant to exposure planning and diver safety.

Why can oxygen become a hazard underwater?

At the surface, oxygen supports normal metabolism. As ambient pressure rises, oxygen partial pressure rises too, unless the breathing mixture is adjusted; at sufficiently high exposure, oxygen can affect the central nervous system and other tissues.

Central nervous system oxygen toxicity may involve visual or auditory disturbances, nausea, twitching, dizziness, or convulsions. A seizure underwater can be especially dangerous because a diver may lose control of the regulator and airway. The likelihood and timing of symptoms depend on exposure conditions and the individual, so oxygen risk is not captured by the mixture alone.

What does “oxygen sensitivity” mean?

In this research area, oxygen sensitivity refers to variation among people in how they respond to elevated oxygen exposure. Screening asks whether some measurable response, history, or test can help distinguish people who may be more susceptible from those who appear less so.

That question is difficult because a response during one exposure does not necessarily predict a response during another. Exercise, carbon dioxide retention, stress, temperature, depth, exposure duration, and breathing-gas composition can all affect the physiological setting in which oxygen acts. A screening result therefore needs to be interpreted in relation to the conditions under which it was obtained.

Partial pressure: the pressure contributed by oxygen in the breathing gas, which changes with ambient pressure.
Central nervous system toxicity: acute effects of elevated oxygen exposure that can include convulsions.
Individual variability: differences in response that may reflect both biological variation and exposure conditions.
Screening: a proposed way to assess risk, not a guarantee that an individual will or will not experience toxicity.

How do studies examine the screening question?

Studies of oxygen sensitivity can compare responses during controlled hyperbaric exposures, using a defined breathing gas and carefully managed exposure conditions. Researchers may observe symptoms or physiological changes and examine whether those measures vary between participants or track with other characteristics.

Test conditions matter. A comparison is most informative when pressure, oxygen exposure, activity, and other relevant factors are controlled or recorded. Because oxygen toxicity can be unpredictable, the safety of participants is central: exposure protocols require supervision, predefined limits, and the ability to respond promptly to symptoms.

The broader methodological challenge is prediction. A test must do more than detect a response under one set of conditions; it must help estimate risk in the exposures where a decision is needed. Screening also has to balance the consequences of false reassurance against the consequences of excluding someone unnecessarily.

Why does this matter to divers and clinicians?

Divers may encounter elevated oxygen partial pressures in technical, military, scientific, or medical settings. Exposure management already considers the oxygen content of the gas and the pressure and duration of exposure. Individual sensitivity raises a further question: whether a general exposure plan adequately accounts for differences in response.

For diving physicians and hyperbaric clinicians, screening is relevant to assessment and risk management, but it does not replace clinical judgment or exposure controls. A diver’s medical history, the planned exposure, and the circumstances of the work all matter. Anyone with a concern about fitness for diving or hyperbaric treatment should consult a diving-medicine physician.

Where does this research fit in diving medicine?

Oxygen toxicity sits alongside decompression illness, barotrauma, and other pressure-related problems as a core concern in diving and hyperbaric medicine. Research into oxygen sensitivity connects basic physiology—how tissues respond to oxygen under pressure—with operational questions about who may be exposed and how that exposure should be managed.

The field must distinguish a person’s underlying susceptibility from the effects of a particular dive or treatment. That distinction is hard to make when exposures differ and acute responses are not perfectly predictable. Screening research therefore remains tied to the practical details of exposure design, observation, and medical oversight.

Frequently asked questions

Does oxygen sensitivity mean an allergy to oxygen?

No. The term concerns variation in response to elevated oxygen exposure, not an allergic reaction to oxygen at ordinary breathing conditions.

Can a screening test guarantee that oxygen toxicity will not occur?

No screening result can guarantee safety. Response depends on exposure conditions as well as individual factors, so gas choice, pressure, duration, and appropriate supervision remain important.

Who should discuss oxygen exposure concerns with a physician?

Divers and others facing planned hyperbaric exposure who have concerns about their health or fitness should discuss them with a diving-medicine physician, who can consider the individual and the planned exposure.

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