How to read a hyperbaric study
Hyperbaric therapy means breathing inside an environment pressurized above normal atmospheric pressure. Pressure and oxygen concentration are separate variables, and the delivered dose also depends on session length, frequency, and total sessions. For each study below, look at five things first:
- Pressure, in ATA
- Breathing gas: room air, enriched oxygen, or near 100% oxygen
- Minutes at pressure per session
- Schedule: sessions per week and total sessions
- Comparator: sham exposure, no treatment, or none
Then check who was studied and what was measured. A change in a blood marker is not the same as a clinical outcome, and a result in one population does not carry over to another.
Studies
Showing 7 of 7 studies.
Stem and progenitor cells | Prospective single-arm study
Hyperbaric air mobilizes stem cells in humans; a new perspective on the hormetic dose curve
MacLaughlin KJ, et al. Frontiers in Neurology, 2023. doi:10.3389/fneur.2023.1192793
- Population
- 10 healthy volunteers aged 34 to 35
- Pressure
- 1.27 ATA (4 psig)
- Breathing gas
- Room air
- Session length
- 90 minutes
- Schedule
- Monday to Friday, 10 exposures over 2 weeks
- Comparator
- Each participant served as their own control (blood drawn before the first exposure)
What the authors reported: The authors measured mobilization of stem and progenitor cells and changes in cytokines in blood samples after hyperbaric air exposures.
Limits to keep in mind: Ten participants and no separate control group. The endpoint is circulating cell counts, which is not the same as tissue regeneration or a clinical benefit.
Mild traumatic brain injury | Randomized crossover trial
Hyperbaric Oxygen Therapy Can Improve Post Concussion Syndrome Years after Mild Traumatic Brain Injury - Randomized Prospective Trial
Boussi-Gross R, et al. PLOS ONE, 2013. doi:10.1371/journal.pone.0079995
- Population
- 56 patients with mild traumatic brain injury, 1 to 5 years after injury, with prolonged post-concussion syndrome
- Pressure
- 1.5 ATA
- Breathing gas
- 100% oxygen
- Session length
- 60 minutes
- Schedule
- 5 days per week, 40 sessions
- Comparator
- A 2-month control period with no treatment (crossover design)
What the authors reported: The authors reported improvements in brain function measures and quality of life after the treatment period, and concluded that the protocol can induce neuroplasticity in this population.
Limits to keep in mind: The control condition was no treatment, not a sham exposure, so participants knew when they were being treated.
Mild traumatic brain injury | Randomized controlled trial
Effects of Hyperbaric Oxygen on Symptoms and Quality of Life Among Service Members With Persistent Postconcussion Symptoms: A Randomized Clinical Trial
Miller RS, et al. JAMA Internal Medicine, 2015. doi:10.1001/jamainternmed.2014.5479
- Population
- 72 military service members with persistent post-concussion symptoms
- Pressure
- 1.5 ATA
- Breathing gas
- 100% oxygen delivered by a hood
- Session length
- 60 minutes
- Schedule
- Weekdays, 40 sessions
- Comparator
- Sham sessions of room air at 1.2 ATA, and a third group with no chamber sessions
What the authors reported: No difference was observed between the oxygen group and the sham group. Both chamber groups showed more symptom improvement than the group that received routine care alone. The authors concluded that oxygen showed no benefit over sham compressions.
Limits to keep in mind: The sham arm was itself a pressurized exposure (room air at 1.2 ATA), so the trial compared two pressurized conditions. Read alongside the trial above, it shows why protocols must be compared by dose and control condition, not by name.
Stroke | Randomized controlled trial
Hyperbaric Oxygen Induces Late Neuroplasticity in Post Stroke Patients - Randomized, Prospective Trial
Efrati S, et al. PLOS ONE, 2013. doi:10.1371/journal.pone.0053716
- Population
- 74 post-stroke patients enrolled (15 were excluded)
- Pressure
- 2 ATA
- Breathing gas
- 100% oxygen
- Session length
- 90 minutes
- Schedule
- 5 days per week, 40 sessions over 2 months
- Comparator
- A 2-month control period with no treatment
What the authors reported: The authors reported neurological improvements after the treatment period in patients at chronic late stages after stroke.
Limits to keep in mind: The control condition was no treatment, not a sham exposure.
Post-COVID condition | Randomized controlled trial
Hyperbaric oxygen therapy improves neurocognitive functions and symptoms of post-COVID condition: randomized controlled trial
Zilberman-Itskovich S, et al. Scientific Reports, 2022. doi:10.1038/s41598-022-15565-0
- Population
- 73 patients with post-COVID condition (37 treatment, 36 sham)
- Pressure
- 2 ATA
- Breathing gas
- 100% oxygen by mask, with 5-minute air breaks every 20 minutes
- Session length
- 90 minutes
- Schedule
- 5 sessions per week, 40 sessions over 2 months
- Comparator
- Sham: 21% oxygen by mask at 1.03 ATA for 90 minutes
What the authors reported: In this sham-controlled, double-blind trial, the authors reported improvements in cognitive, psychiatric, fatigue, sleep, and pain symptoms in the treatment group compared with sham.
Limits to keep in mind: A single-center trial. This research does not mean an OxyHealth chamber is cleared for this use.
Healthy aging | Randomized controlled trial
Cognitive enhancement of healthy older adults using hyperbaric oxygen: a randomized controlled trial
Hadanny A, et al. Aging, 2020. doi:10.18632/aging.103571
- Population
- 63 healthy adults older than 64
- Pressure
- 2 ATA
- Breathing gas
- 100% oxygen by mask, with 5-minute air breaks every 20 minutes
- Session length
- 90 minutes
- Schedule
- 5 sessions per week, 60 sessions over 3 months
- Comparator
- A control arm of 30 participants (no sham exposure described in the abstract)
What the authors reported: The authors reported a significant group-by-time interaction in global cognitive function after the treatment period compared with control (p=0.0017).
Limits to keep in mind: Healthy older adults only. Findings should not be extended to other populations.
Healthy aging | Prospective single-arm study
Hyperbaric oxygen therapy increases telomere length and decreases immunosenescence in isolated blood cells: a prospective trial
Hachmo Y, et al. Aging, 2020. doi:10.18632/aging.202188
- Population
- 35 healthy, independently living adults aged 64 and older
- Pressure
- 2 ATA
- Breathing gas
- 100% oxygen by mask, with 5-minute air breaks every 20 minutes
- Session length
- 90 minutes
- Schedule
- 5 sessions per week, 60 sessions over 3 months
- Comparator
- None. The authors list the lack of a control group as a limitation.
What the authors reported: The authors reported that telomere length in several types of isolated blood cells increased by more than 20% and that the number of senescent T helper cells decreased after the exposures.
Limits to keep in mind: No control group. The endpoints are laboratory measures in blood cells, not clinical outcomes such as lifespan or disease.
Study protocols are not recommendations
The pressures, gases, and session counts listed here describe what researchers did in each study. They are not instructions for any individual. A qualified clinician determines whether hyperbaric therapy is appropriate and sets the breathing gas, pressure, duration, and frequency.
Several of these studies involve conditions outside the cleared indications for hyperbaric chambers. That research does not mean an OxyHealth chamber is cleared for those uses. For the difference between device clearance and clinical use, see what FDA clearance means.