The Physiological Basis of Decompression is a 1989 publication by Vann addressing the bodily processes that underpin decompression. Presented in a workshop devoted to undersea and hyperbaric medicine, its subject connects pressure exposure with the risks of returning to the surface, a central concern for divers, clinicians and researchers.
What does decompression physiology examine?
Underwater, ambient pressure rises with depth. The gases a diver breathes are delivered at pressures that change with the surrounding environment, and some of those gases dissolve in body tissues. On ascent, pressure falls and the body must eliminate excess inert gas while avoiding harmful bubble formation.
Decompression physiology examines how these linked processes unfold: gas exchange in the lungs, transport in blood, uptake and release by tissues, and the effects of changing pressure. It provides a framework for understanding why time at depth and the rate and pattern of ascent matter, without reducing the body’s response to a single simple rule.
Why can inert gas become a medical concern?
Nitrogen is the principal inert gas in ordinary compressed-air diving. As pressure increases, more nitrogen can enter the body’s tissues; during ascent, it moves back toward the lungs for removal. If pressure decreases faster than gas can be safely eliminated, bubbles may form or grow in tissues and circulation, contributing to decompression illness.
Decompression illness can involve varied symptoms and mechanisms, from pain to serious neurological or cardiopulmonary problems. The risk is not determined by depth alone: exposure duration, ascent profile, breathing gas, individual physiology and other conditions can all matter. This is why decompression is studied as a physiological process rather than treated as a simple calculation.
Which concepts help explain decompression?
Several connected ideas help readers navigate the subject. They are useful for interpreting dive procedures and research, but no single concept captures every aspect of human response to pressure.
- Partial pressure: the contribution of an individual gas to the total pressure of a breathing mixture.
- Gas solubility and diffusion: how gases enter, move through and leave blood and tissues.
- Tissue compartments: models that represent differences in the speed of gas uptake and elimination among tissues.
- Supersaturation and bubbles: conditions in which dissolved gas may come out of solution as ambient pressure falls.
- Decompression stress: the physiological burden associated with pressure exposure and gas elimination, which is not always directly observable.
How does physiology inform dive practice and care?
Decompression procedures aim to manage pressure reduction and give the body time to release inert gas. Dive planning, ascent practices and decompression schedules draw on models of gas exchange, while recognising that models simplify complex biology. A schedule is not a guarantee that decompression illness cannot occur.
For diving physicians and hyperbaric clinicians, physiological understanding supports assessment of possible decompression illness and consideration of its mechanisms. Hyperbaric treatment uses pressure and oxygen in clinical care, but decisions depend on the diver’s condition and require qualified medical judgment. Anyone with symptoms after diving should seek urgent assessment from a diving-medicine physician or emergency service.
Where does this subject fit in diving research?
Decompression has long been a meeting point for physiology, mathematical modelling, operational practice and clinical medicine. Research in the field asks how pressure exposure translates into gas movement and biological effects, how well models represent those processes, and how decompression-related risks can be assessed and managed.
As a workshop publication in undersea and hyperbaric medicine, Vann’s work belongs to this broader conversation about the physiological basis of safe pressure change. The topic remains relevant across recreational, commercial and scientific diving, as well as hyperbaric practice, because each depends on understanding how the body responds when ambient pressure changes.
Frequently asked questions
What is decompression?
Why does inert gas matter in diving?
Who should assess symptoms after a dive?
Citation details
- Title: The Physiological Basis of Decompression
- Authors: Vann, RD
- Year: 1989
- Published in: 38th Undersea and Hyperbaric Medical Society Workshop. UHMS Publication Number 75(Phys)6-1-89. Bethesda: Undersea and Hyperbaric Medical Society; 1989; 437 pages
- Repository record: Rubicon Research Repository, handle 123456789/6853
This page is an original summary written by the Rubicon editors from the publication’s bibliographic record. It does not reproduce the paper, its abstract or its data; consult the publication itself for its methods and findings.
Related reading on Rubicon
- How Decompression Sickness Develops: Physiological
- Decompression Sickness vs. Arterial Gas Embolism
- Decompression Sickness vs. Immersion Pulmonary Edema
- Decompression Sickness: Causes and Risk Reduction
- Physiological Measures in Special Operations Research
- Misclassification of Decompression Illness: Research Summary
- More on Diving Science
- Browse the Research Library
