In the blog category “From our community”, we address treatments that are being discussed controversially by people affected by Long COVID and health care professionals. In the Altea forum, in stories, and in discussions with those affected, we have seen a number of treatment suggestions that are not officially recommended (yet). To help judge the safety and effectiveness of these treatments, we are exploring the science behind them. We are aiming to provide an overview of the available evidence, evaluate whether or not the available data is reliable, and summarize which risks might be associated with these treatments. Today, we want to assess oxygen therapies.
What is hyperbaric oxygen therapy (HBOT)?
The air we breathe usually contains 21% oxygen. Hyperbaric oxygen therapy (HBOT) involves breathing 100% (pure) oxygen in a pressurized environment, typically inside a hyperbaric chamber. Being used for decades, HBOT is a treatment for several conditions, including non-healing wounds, decompression sickness in divers, carbon monoxide poisoning, hearing and vision loss, radiation injury and certain types of infections. However, it is important to note that this procedure is still being reviewed for the treatment of COVID-19 and Long COVID by regulatory agencies, such as the European Medicines Agency (EMA) or the U.S. Food and Drug Administration (FDA).
HBOT is safe for most people, but there are potential risks associated with the procedure including ear and sinus pain, middle ear injuries, temporary vision changes and lung collapse (rare). The high concentrations of oxygen during HBOT also pose a fire hazard, which is why HBOT should be performed in accredited facilities only.
HBOT improves heart function, a small study found
Due to its safety and effectiveness in some conditions, HBOT is becoming an attractive therapy for treating some symptoms of Long COVID. For example, a small randomized controlled trial suggests that HBOT can be beneficial in Long COVID patients with impaired heart function. The study included 29 patients who suffered from a myocardial deformation which presented as reduced global longitudinal strain (GLS) three months after infection with the SARS-CoV-2 virus. GLS is a measure of the lengthwise contraction and relaxation of the heart muscle, which can be detected on an echocardiogram (ECG).
Of the 29 patients, 16 received HBOT (40 sessions over eight weeks) and 13 received sham (normal air). The 16 patients who underwent real HBOT experienced a significant improvement in their heart function compared with patients in the control group. Although these results are encouraging, the study authors concluded that more research is needed to evaluate long-term outcomes and to determine which patients will benefit the most.
HBOT may improve cognitive symptoms.
HBOT has also been investigated in Long COVID patients with fatigue and cognitive problems. Another randomized controlled trial from 2022 showed that patients who received HBOT reported improvements in brain fog, memory, and attention. The study included 37 patients who received therapy and a control group of 36 who did not. The treatment group also experienced more energy, better sleep, less pain, and fewer psychiatric symptoms after 40 daily HBOT sessions. The control group did not experience any remarkable improvements in these symptoms.
In this study, the investigators used magnetic resonance imaging (MRI) before and after therapy to detect whether HBOT has changed the patients’ brains. Interestingly, analyses of MRI scans showed significant changes in some parts of the brain that are involved in cognitive activities. These results indicate that HBOT may improve brain function by increasing blood flow and neuroplasticity (the brain´s ability to change and adapt) in areas that are important for thinking and emotions.
This study, however, has some important drawbacks. Notably, patients were evaluated only up to three weeks after the final session, which means that potential long-term benefits or damages caused by HBOT remain unclear.
Longer-term effects of HBOT
Positive results were also reported from a more recent clinical pilot study conducted by an Austrian research group. This study investigated the immediate and long-term effects of HBOT in 59 patients with Long COVID who received ten subsequent HBOT sessions. Patients answered standardized questionnaires on their health status before the first and after the last HBOT session and three months afterward.
After treatment, patients reported significant improvements in several measures. This included better physical activity and social interaction, increased level of energy, and less pain. Improvements in physical activities and socializing persisted after three months.
Similar to the previous one, this study has some limitations, including the small number of enrolled patients. This makes it difficult to draw strong conclusions about the effectiveness of HBOT. Clinical trials should involve a sufficient number of patients to reliably demonstrate whether an intervention is effective.
Intermittent hypoxia-hyperoxia treatment (IHHT) for Long COVID
Intermittent hypoxia-hyperoxia training (IHHT) has emerged as another potential therapy for patients with Long COVID. This procedure involves alternating periods of breathing low oxygen (hypoxia; around 10% oxygen) and high oxygen (hyperoxia; 30-40% oxygen).
A small study suggests that IHHT could boost athletic performance, while improving heart and lung efficiency, heart health and the ability to exercise in patients with heart failure (a condition when the heart does not pump enough blood). Some early studies on IHHT have also demonstrated promising results in patients with Long COVID. For example, some data suggests that IHHT could improve functional capacity and quality of life in Long COVID patients who were admitted to a hospitalized rehabilitation program. Functional capacity is the ability of an individual to perform tasks and activities in their daily life.
Intermittent hypoxia-hyperoxia training (IHHT) involves alternating periods of breathing low oxygen (hypoxia) and high oxygen (hyperoxia). In hyperbaric oxygen treatment (HBOT), patients breathe a constant level of 100% oxygen.
From our community
Members of our community report an intake of nutritional supplements in connection with their oxygen therapy. Notably, no supplement regimen was added in any of the mentioned studies. Moreover, multistep oxygen therapy by Ardenne is often mentioned in German speaking alternative medicine. However, we could not find any internationally peer-reviewed data on this specific therapy form and no publications since the 1990s.
Promising but not for everyone
Taken together, HBOT is a complex and not fully understood procedure that is currently not approved by the regulatory agencies for the treatment of Long COVID. Initial results from studies are promising but also point out that HBOT and IHHT merit further investigations in larger, high-quality clinical trials with a longer follow-up. For now, we do not have enough information on how effective it is, how long its effects last, and if it is safe in patients with Long COVID. Due to these reasons, HBOT is only available in private clinics at a high cost.
Some patients with specific causes of Long COVID might benefit from HBOT but for most, it might simply not work or be even unsuitable: Patients with a collapsed lung, high fever, certain ear and eye conditions, or receiving specific medication should not receive it. As with all experimental therapy forms, supervision and consultation with healthcare professionals are a must to judge the risk of unwanted outcomes.
