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Energy & sleep

Sleep apnoea

A 2025 systematic review gathered what is known about hyperbaric oxygen and sleep-related breathing problems. It found the idea promising in theory but the human evidence very thin: one small Chinese trial in obstructive sleep apnoea and one chamber study in miners at altitude. Hyperbaric oxygen is not an alternative to CPAP or other treatment from your GP or sleep service.

Evidence so far
Early
Reading timeAbout 12 minutes

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Why this is being studied

In obstructive sleep apnoea the airway narrows or closes again and again during sleep, so oxygen levels drop, the brain jolts awake for a moment, and sleep is broken without the person realising. It is common, often undiagnosed, and linked over time to high blood pressure, heart problems and daytime exhaustion. The standard treatment is CPAP, a mask that keeps the airway open with gentle air pressure. Researchers are interested in hyperbaric oxygen because it raises oxygen in the blood and tissues and may affect how the brain controls breathing, but very few human studies exist. If you snore loudly, stop breathing at night or wake up gasping, please speak to your GP first.

Where the evidence stands

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The mechanism

What is going on, and why this might help

What is going on in the body

In obstructive sleep apnoea, the muscles of the throat relax during sleep and the soft tissue falls back, narrowing or closing the airway. Each pause lowers blood oxygen until the brain briefly wakes the person to restart breathing. This can happen dozens of times an hour. The repeated drops and rises in oxygen act like small stresses on the body, raising blood pressure, inflammation and strain on the heart, while broken sleep leaves people exhausted during the day. Doctors measure severity with the apnoea-hypopnoea index (AHI), the number of pauses and shallow breaths per hour.

Where oxygen comes in

Hyperbaric oxygen dissolves extra oxygen into the blood plasma. Researchers suggest a course of sessions might reduce inflammation in the throat tissues, improve how the throat muscles work and make the brain's breathing control less prone to swinging between over- and under-breathing. These ideas come largely from studies of ordinary oxygen and of other conditions. One important difference is that hyperbaric sessions happen during the day, while apnoea happens at night, so any benefit would have to come from lasting changes rather than from the oxygen itself.

What ordinary oxygen tells us

Studies of breathing extra oxygen through the night show it raises oxygen levels but does not stop the airway closing. CPAP reduces the pauses far more, and oxygen alone can make some pauses last longer and let carbon dioxide build up. This is why oxygen is not used instead of CPAP.

How solid is this

A 2025 systematic review found almost no direct human evidence: one small Chinese trial with no comparison group that did not have hyperbaric oxygen, and one chamber study in miners at high altitude. The authors describe hyperbaric oxygen for sleep-related breathing problems as experimental. It should not replace a sleep study, CPAP or any treatment from your GP or sleep service.

Explainer illustration

The studies

Every study is laid out the same way: what the researchers wanted to find out, who took part, what they actually did, what they found, why it might work and where the limits are. No jargon, and a link to the original if you want to read it yourself.

Each study is laid out the same way: what the researchers asked, who took part, what they did, what they found, why it might work, and where the limits are. The clinician layer at the end of each one carries the numbers.

Paper 1

Hyperbaric oxygen therapy and its physio-mechanical effects on sleep breathing disorder: a systematic review

Duong-Quy et al. · Pulmonary Therapy · 2025 · systematic review

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What they asked

This review set out to gather every human study of hyperbaric oxygen in sleep-related breathing problems, including obstructive sleep apnoea, where the airway closes, and central sleep apnoea, where the brain briefly stops sending the signal to breathe. It also looked at how hyperbaric oxygen might work on breathing control.

Who took part

This was a review of existing studies rather than a new trial. The authors, from Vietnam, France, Germany and the USA, searched six major research databases and trial registers.

What they did

They summarised the studies they found in a table of ten representative papers and discussed possible mechanisms. They did not pool results in a meta-analysis or formally rate the quality of each study.

What they found

Only one study in the table tested hyperbaric conditions in sleep-related breathing: 24 gold-mine workers living at around 4,000 metres who slept in a chamber set to simulate a lower altitude. Their overnight oxygen levels rose from about 84 to 93 per cent, with fewer oxygen dips and fewer night-time arousals. The other studies in the table were about sleep in brain injury, long COVID, stroke and Parkinson's disease, not apnoea. The authors describe hyperbaric oxygen for sleep-related breathing problems as promising but experimental.

Why it might work

The authors suggest hyperbaric oxygen could steady the brain's breathing control, raise the threshold at which the brain jolts awake and reduce inflammation in the airway. These ideas are based on physiology and on studies of ordinary oxygen, not on apnoea trials.

Limits

Independent reading of the review shows it found no hyperbaric trial measuring the apnoea-hypopnoea index in obstructive sleep apnoea, despite its conclusion mentioning possible improvements. The miners slept in the chamber overnight, which is very different from daytime sessions. There was no formal quality assessment or registered plan.

Paper 2

The observation on hyperbaric oxygen therapy and pharyngeal neuromuscular electrical stimulation in patients with obstructive sleep apnea hypopnea syndrome

Tan, Long and Deng · Chinese Journal of Rehabilitation Medicine · 2013 · randomised comparison of two treatments, n=30

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What they asked

This small Chinese study asked whether adding electrical stimulation of the throat muscles to a course of hyperbaric oxygen would help obstructive sleep apnoea more than hyperbaric oxygen alone.

Who took part

Thirty adults with obstructive sleep apnoea confirmed by symptoms and an overnight sleep study, split at random into two groups of 15.

What they did

Both groups had 10 sessions of hyperbaric oxygen. One group also had neuromuscular electrical stimulation of the throat muscles, intended to strengthen them so the airway is less likely to collapse. The abstract does not give the pressure or session length. The overnight sleep study was repeated afterwards.

What they found

The group with both treatments had about 30 fewer breathing pauses and shallow breaths per hour, and their lowest overnight oxygen level rose by about 15 per cent. The authors report that the combination did better than hyperbaric oxygen alone, but the abstract does not give the results for the hyperbaric-only group.

Why it might work

Throat muscle stimulation targets the airway collapse directly. The authors suggest hyperbaric oxygen may reduce swelling and improve muscle function in the throat, supporting the stimulation.

Limits

Thirty people, a short course and no group without hyperbaric oxygen, so this study cannot show whether hyperbaric oxygen itself helps. Only the abstract is publicly available and some of its figures do not add up. It has not been repeated by other researchers.

Paper 3

Obstructive sleep apnea and oxygen therapy: a systematic review of the literature and meta-analysis

Mehta et al. · Journal of Clinical Sleep Medicine · 2013 · meta-analysis of 14 studies, n=359 (ordinary oxygen, not hyperbaric)

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What they asked

This review is about ordinary oxygen through the night, not hyperbaric oxygen. It is included because it is the closest well-studied comparison and shows what extra oxygen does and does not do in sleep apnoea. The authors asked whether night-time oxygen could stand in for CPAP.

Who took part

Fourteen studies with 359 people with obstructive sleep apnoea, including randomised trials comparing oxygen with CPAP or with a fake CPAP machine.

What they did

They pooled results for overnight oxygen levels, the number of breathing pauses per hour (AHI), how long each pause lasted, daytime sleepiness and blood pressure.

What they found

Oxygen raised overnight oxygen levels about as well as CPAP. But CPAP reduced the number of breathing pauses far more than oxygen, and oxygen was not clearly better than fake CPAP on pauses. In several studies oxygen made the pauses last longer, and it carries a risk of carbon dioxide building up.

Why it matters here

Raising oxygen treats a consequence of sleep apnoea, not the cause, which is the airway closing. Any benefit from daytime hyperbaric sessions would need to come from lasting changes to the airway or breathing control, and that has not been shown.

Limits

Many of the studies were small and short, and several had no comparison group. Since this review, newer analyses have continued to find that CPAP, not oxygen, is the treatment of choice.