Several research’s and studies examine the influence of exposure to hyperbaric oxygen (HBO2) and decompression on various facets of the immune response. Potential changes during exposure include a decrease in the CD4+ CD8+ ratio, a decreased proliferation of lymphocytes, and an activation of neutrophils with migration to regions of high oxygen pressure.

There may also be an activation of the complement cascade during decompression. Clinical indicators of overall immune suppression include a decreased response to antigens, a weakening of autoimmune responses, and a slower rejection of allografts.

Source: Brenner I, Shephard RJ, Shek PN. Immune function in hyperbaric envi Save ronments, diving, and decompression. Undersea & Hyperbaric Medicine: Journal of the Undersea and Hyperbaric Medical Society, Inc. 1999 ;26(1):27-39.


Oxygen tensions play an important role in the outcome of infections. Oxygen is cidal or static for microorganisms that lack defenses against oxidants. Hyperoxia and hyperbaric oxygen exert antimicrobial effects by increasing the intracellular flux of reactive oxygen species. 

In bacteria, such species cause DNA strand breaks, degradation of RNA, inhibition of amino acid biosynthesis, and inactivation of membrane transport proteins. Oxygen tensions also affect the activity of antimicrobial agents. In general, hyperoxia potentiates while anaerobiosis decreases the activity of many antimicrobial drugs. 

With regard to host defenses, hyperoxia elevates oxygen tensions in infected tissues to levels that facilitate oxygen-dependent killing by leukocytes. Prolonged hyperoxia inhibits DNA synthesis in lymphocytes and impairs chemotactic activity, adherence, phagocytic capacity, and generation of the oxidative burst in polymorphonuclear leukocytes and macrophages.

Source: Matthew K. Park, Roy A. M. Myers, Louis Marzella, Oxygen Tensions and Infections: Modulation of Microbial Growth, Activity of Antimicrobial Agents, and Immunologic Responses, Clinical Infectious Diseases, Volume 14, Issue 3, March 1992, Pages 720–740,

See the section below for detailed information in research and studies related to your specialty.


Physiologic and biochemical rationale for treating COVID-19 patients with hyperbaric oxygen

The Effects of Hyperbaric Oxygen on Rheumatoid Arthritis: A Pilot Study

HBO Therapy in Hematology and Immunology

Oxygen Tensions and Infections: Modulation of Microbial Growth, Activity of Antimicrobial Agents, and Immunologic Responses

Hyperbaric oxygenation in the comprehensive therapy of patients with rheumatoid arthritis (clinico-immunologic study)

Hyperbaric oxygen in systemic inflammatory response

Effect of hyperbaric oxygen treatment on immunological parameters in multiple sclerosis

Modification of in Vivo and in Vitro TNF-α, IL-1, and IL-6 Secretion by Circulating Monocytes During Hyperbaric Oxygen Treatment in Patients with Perianal Crohn’s Disease

Hyperbaric oxygen inhibits stimulus‐induced proinflammatory cytokine synthesis by human blood‐derived monocyte‐macrophages

Immune function in hyperbaric environments, diving, and decompression.

Immunosuppression by hyperbaric oxygen

Evolving career of hyperbaric oxygen in sepsis: From augmentation of oxygen delivery to the modulation of the immune response

Hyperbaric oxygen treatment attenuates the pro-inflammatory and immune responses in apolipoprotein E knockout mice

The effect of hyperbaric oxygen on cellular immunity and the study of its mechanism

Suppressive effect of hyperbaric oxygenation on immune responses of normal and autoimmune mice.

Application of hyperbaric oxygen in liver transplantation

Anti-Inflammatory Effects of Hyperbaric Oxygenation during DSS-Induced Colitis in BALB/c Mice Include Changes in Gene Expression of HIF-1α, Proinflammatory Cytokines, and Antioxidative Enzymes

Suppression of humoral antibody synthesis on exposure to hyperbaric oxygenation

Impact of hyperbaric oxygen therapy on the clinical course of acute pancreatitis and systemic inflammation response syndrome

What are the benefits of HBOT?


Hyperbaric Oxygen Therapy improves the quality of life for the patient in many areas when standard treatment isn’t working

Can HBOT help you?


Yes. It can benefit conditions where low oxygen levels (hypoxia) and inflammation are present

The Oxygen for Life


Oxygen can be used therapeutically for a wide range of conditions where tissues have been damaged by oxygen deprivation