Medical Matters > Treatment: Hyperbaric Oxygen Therapy (HBOT)

ME Essential Summer 2023


Has there ever been a clinical trial to assess the use to hyperbaric oxygen (HBO) in ME?  I know that HBO is being used by people with multiple sclerosis as well as ME – so it seems that there are positive effects in the case of neurological diseases. I’ve also read that a clinical trial involving people with Long Covid has found some beneficial effects.


Hyperbaric Oxygen Therapy (HBOT) is a complementary therapy where you sit in a pressurised chamber and breathe oxygen through a mask. It is a means of providing high-pressure oxygen to body tissues. ‘Hyper’ means increased and ‘baric’ relates to pressure. Oxygen makes up 21% of the air that we ordinarily breathe. HBOT involves breathing 100% oxygen, intermittently, usually through a mask, inside a hyperbaric chamber.

Breathing 100% oxygen under pressure allows oxygen to be dissolved into the plasma, the liquid part of the blood. By intermittently increasing the amount of oxygen in the tissues, the body’s natural healing process can be enhanced in some situations. HBOT also encourages new blood vessels to grow, increases the ability of the body to fight infection and kill bacteria, and can reduce swelling. Conditions where there is good evidence that HBOT is effective include divers with decompression illness, diabetic foot ulcers, carbon monoxide poisoning, radiation tissue damage and other hard to-heal wounds. There is also some evidence that HBOT could be beneficial in the treatment of stroke.

In HBOT, oxygen is increased to almost 100% and is breathed in through a mask while seated inside a pressurised chamber. The increased pressure allows the additional oxygen to saturate the blood. These extra oxygen molecules are not bound to red blood cells, so they are free to diffuse into the body tissue, which can stimulate and accelerate healing.

In relation to HBOT slowing or reversing Multiple Sclerosis (MS), a Cochrane Review found that the majority of trials did not find any significant benefit in treating MS, and the 2022 NICE Guideline on MS does not include HBOT as a recommendation. However, despite this lack of evidence, there are many anecdotal reports that it can help to relieve symptoms and there are numerous HBOT centres around the UK treating people with MS. HBOT centres are willing to accept people with ME/CFS and Long Covid, but beware of the inflated promises that some of these centres are using to attract business and ensure you can afford it before making a committment. You should also ensure you can comfortably travel to and from the centre.

There hasn’t been a proper robust clinical trial to evaluate HBOT as a possible form of treatment for ME/CFS. We do, however, have some results from one small observational study. It involved 16 people who knew they were receiving HBOT, contained no control group, and did not involve any long term follow up. It does not therefore have the status of a proper clinical trial (see below). A similar study has been completed more recently in Long Covid (below) that again found benefits but was not adequately controlled and only included 10 people. There are clearly some theoretical reasons why HBOT might be effective in ME/CFS and Long Covid in regard to relieving symptoms of fatigue and cognitive dysfunction and a full clinical trial would be worth doing. But this is not something that we could add to the ME Association Ramsay Research Fund as a priority study at the moment although we would be willing to consider a high-quality application if a researcher would like to submit one.

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Information provided by The ME Association should not be construed as medical advice. Don't assume any new or worsened symptoms are simply the result of having ME/CFS or Long Covid. We recommend that any information you deem relevant is discussed with your NHS GP as soon as possible. It is important that you seek personalised medical advice from the GP who is in charge of your care and who knows you well.

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