Hyperbaric oxygen therapy (HBOT) has emerged as a potential treatment for the persistent and often debilitating illness known as Long COVID. Long COVID, or Post-Acute Sequelae of SARS-CoV-2 infection (PASC), refers to a wide range of symptoms that continue or develop weeks or months after the initial infection. This chronic condition affects multiple organ systems and can include fatigue, cognitive difficulties, and shortness of breath, for which established treatments are currently limited.
Understanding Hyperbaric Oxygen Therapy
Hyperbaric Oxygen Therapy is a medical treatment where a person breathes 100% oxygen while inside a pressurized chamber. The pressure within the chamber is elevated above sea level, typically ranging from 1.5 to 3.0 atmospheres absolute (ATA). This elevated pressure and high-concentration oxygen dramatically increase the amount of oxygen dissolved in the blood plasma.
Under hyperbaric conditions, oxygen is forced directly into the liquid component of the blood, a process called hyperoxygenation. This allows oxygen to reach tissues that may have compromised blood flow or poor circulation. This delivery method is designed to maximize oxygen supply to all parts of the body, enhancing the diffusion of oxygen into the cells.
HBOT’s Targeted Action on Long COVID
Scientists believe HBOT can address several biological drivers of Long COVID symptoms. One primary mechanism is the reduction of chronic, low-grade systemic inflammation, a common feature in many patients. HBOT dampens the immune response by decreasing pro-inflammatory cytokines, such as IL-6 and TNF-\(\alpha\), while promoting anti-inflammatory ones.
The therapy also addresses chronic tissue hypoxia, or inadequate oxygen supply at the cellular level, particularly in the brain and heart. HBOT can bypass areas of impaired microcirculation to reach oxygen-starved tissues, improving mitochondrial function and cellular energy production. This improved oxygenation is crucial for the central nervous system, where it can stimulate neuroplasticity and repair processes.
HBOT may also mitigate microvascular damage and the formation of microclots observed in some Long COVID patients. The increased oxygen tension promotes angiogenesis, the development of new small blood vessels, which helps restore blood flow and relieve tissue hypoxia.
Clinical Research and Treatment Outcomes
Current scientific evidence regarding HBOT for Long COVID comes from a growing number of clinical trials. Initial randomized controlled trials have demonstrated significant improvements across several common symptoms. Patients receiving HBOT have shown improved outcomes in areas like fatigue, cognitive function, and quality of life when measured against control groups.
Specific cognitive symptoms, often referred to as “brain fog,” such as reduced attention, working memory, and executive function, have shown marked improvement in several studies. One randomized trial reported sustained improvements in patient-reported outcomes, including cognitive symptoms and pain, one year after the treatment concluded. Another study focusing on cardiac function found that HBOT could promote the recovery of left ventricular systolic function in post-COVID patients. While the results are promising, researchers stress that the field is still emerging, and many studies have involved relatively small sample sizes. Continued research is necessary to optimize treatment protocols and establish the long-term efficacy and clinical relevance of HBOT.
Practical Aspects of HBOT Sessions
A typical treatment protocol for Long COVID often involves a high number of sessions over several weeks. Protocols frequently require around 40 daily sessions, administered five days a week, spanning an eight-week period. Each session lasts between 90 and 120 minutes, which includes time for pressurization and depressurization.
The pressure level commonly used is 2.0 to 2.5 ATA, with the patient breathing 100% oxygen. Sessions often incorporate “air breaks,” where the patient temporarily breathes regular air to reduce the risk of oxygen toxicity. HBOT is generally considered safe, but side effects related to pressure changes can occur. These include:
- The most frequent mild side effect is barotrauma, or pressure-related injury, to the middle ear or sinuses, similar to the discomfort experienced during air travel.
- Less common, but more serious, contraindications include an untreated pneumothorax.
- Some patients also report temporary visual changes, such as blurry vision.
- An increase in fatigue during the initial treatments.