How Does Hyperbaric Oxygen Therapy (HBOT) Work?
Pressure is measured in something called atmospheres absolute, or ATA. At sea level, pressure is 1 ATA. During HBOT treatments, the pressure inside the chamber is about 2.0 to 2.5 ATA — similar to the pressure you’d feel if you were 15 feet underwater.
High pressure changes how oxygen works in the body. Under normal conditions, oxygen travels inside red blood cells. When you increase pressure, oxygen can dissolve directly into the plasma, the fluid around the blood cells — so it can reach areas that usually struggle to get enough.
There are two main types of chambers used for treatment:
a clear tube you lie inside
a larger chamber where several people are treated at the same time
Soft-sided or "mild" chambers use much lower pressure and are not the same as medical HBOT.
This is why HBOT is often used for chronic wounds. These wounds often can’t heal because oxygen levels stay too low for the tissue to heal. But when you increase oxygen levels, healing speeds up (Cleveland Clinic, 2023).
HBOT can also be used to treat serious infections. Some parts of the immune system work better when oxygen levels are high. For example, in severe infections that damage skin and muscle, extra oxygen can help the body fight infection. It works even better when used together with surgery and antibiotics.
HBOT also has a direct impact on inflammation and cell repair. But these effects vary from person to person. In some cases, HBOT helps a lot, and in others it has a much smaller effect.
HBOT also doesn’t work on its own. Things like nutrition, inflammation, and overall metabolic health also play a role in how well tissues respond during treatment.
Who Does Hyperbaric Oxygen Therapy (HBOT) Help?
People use HBOT for different reasons. Those reasons tend to fall into three main groups.
To treat conditions like carbon monoxide poisoning or decompression sickness
For injuries and wounds that aren’t healing well.
As an alternative treatment for neurological problems and inflammation. There’s very little research about these uses.
If you’re considering HBOT, start by asking a simple question: what is it supposed to treat? And do I really need it?
Common Uses
Doctors don’t use HBOT for everything. In fact, the Undersea and Hyperbaric Medical Society (UHMS) recognizes only 15 medical conditions where it’s part of standard care.
Decompression sickness
Carbon monoxide poisoning
Certain diabetic foot ulcers
Radiation damage after cancer treatment
Burns
Soft tissue infections
Skin grafts that aren’t healing well
Anemia
Burn injuries
and several others
Researchers are always finding new ways to use hyperbaric oxygen therapy. The list of possible uses now includes traumatic brain injury, concussion symptoms, sudden hearing loss, and PTSD. For example, one controlled trial of veterans with PTSD found that 68% of participants had at least a 30% drop in symptoms, and 39% went into full remission after treatment (Doenyas-Barak et al., 2024).
There’s still a lot we don’t know. Some studies look promising but others show little benefit. And results can look very different from one person to another.
What the Evidence Supports
HBOT usually works best when it’s added to other treatments, not used alone.
Diabetic foot ulcers
Diabetic foot ulcers can be very hard to treat. Once they appear, they often take a long time to heal. Oxygen is important for tissue healing, so some doctors add HBOT as an extra treatment for certain patients. When combined with good wound care, some ulcers may heal quicker. It may also reduce the risk of amputation (Zhang et al., 2022).
Late radiation tissue injury
Radiation therapy can damage skin and bone. Sometimes the effects don't appear until months or even years later. HBOT can sometimes help (Lin et al., 2016). However, the results depend on how severe the injury is and which parts of the body were affected.
Where the Evidence Is Limited
Mild or non-medical hyperbaric chambers
“Mild” hyperbaric chambers have become popular in wellness centers. But they are not the same as medical HBOT because the pressure is much lower. You might leave feeling relaxed or refreshed, but that doesn’t mean the body is healing.
Brain injury and recovery
Injured brain tissue is under stress, and extra oxygen could help it recover. This is especially true soon after an injury. A 2021 research review found that HBOT can help with memory, focus, and quality of life after a stroke (Gottfriend et al, 2021). But the jury is still out, and researchers are still figuring out how HBOT helps.
Long COVID
There's some hope that HBOT might help with lingering COVID symptoms and complications, such as fatigue, brain fog, and persistent low energy. But so far, the results are mixed (Lindsey & Wainwright, 2025).
Safety and Regulation
When done in a hospital with trained staff, HBOT is usually considered a safe treatment. But like any medical treatment, it still carries some risks.
The most common side effects include:
ear discomfort
ear or sinus injury
temporary eyesight changes
seizures (rare)
The risks are higher for people with lung problems, recent ear surgeries, or untreated infections.
The Experience
Sessions last between 60 and 90 minutes. If this is your first time, a technician will explain how the chamber works and show you how to clear the pressure in your ears.
During treatment, you lie inside a single-person tube or sit in a larger pressurized space with other patients. Oxygen is delivered through a mask or a small tube in the nose. You can relax, take a nap, read something, or just sit quietly.
After the session, you can go back to your normal activities.
The Future of Hyperbaric Oxygen Therapy
New research focuses on practical questions. When does the treatment help the most? Which patients are the best candidates? Progress in medicine rarely happens overnight. Studies often follow patients for long periods and look at real-life outcomes, such as how well people are doing in daily life.
There's hope that treatment might also be able to help victims of stroke, PTSD, and mental health.
Putting HBOT in Perspective
Hyperbaric oxygen therapy has a clear role in medicine. When used properly, it can help patients recover.
If you’re considering HBOT for uses that are less well established, start with a few practical questions. What research supports it? What will the treatment process look like? And what kind of results are realistic? Be cautious about promises that sound too good to be true.
HBOT is a real medical treatment, and in the right cases it can help people recover. But it is not a cure-all. Be cautious with promises that sound too good to be true.
