Fatigue After Dry Chamber Dives: Research Summary

By Rubicon Foundation editorial team

5 min read · 31 October 2026

Measurement of fatigue following 18 msw dry chamber dives breathing air or enriched air nitrox is a 2003 journal article by Harris RJ, Doolette DJ, Wilkinson DC and Williams DJ. Published in Undersea Hyperb Med 30(4), it addresses fatigue after simulated dives and the question of how breathing-gas choice relates to a diver’s post-dive state.

Why examine fatigue after a dive?

Fatigue is familiar to divers, but it is not a single physiological measurement. It can include reduced energy, effortful concentration, sleepiness or a sense that physical and mental tasks are harder than usual. Those experiences may overlap, yet they are not interchangeable.

For diving operations, the distinction matters. A diver may need to manage equipment, communicate, travel or make decisions after surfacing. Understanding when fatigue occurs and how it is assessed can help researchers frame post-dive performance and recovery as questions for both diving science and operational planning.

What does a dry chamber dive model?

A dry chamber dive recreates increased ambient pressure without immersing the participant in water. At 18 metres of seawater (msw), pressure exposure is part of the dive model, while conditions such as cold, water movement and swimming against resistance are not reproduced in the same way as in an open-water dive.

This controlled setting helps researchers focus on selected aspects of pressure exposure and gas breathing. It also defines what the results of such research can address: chamber observations do not automatically capture every physical and environmental demand of a real dive.

What is the relevance of air and enriched air nitrox?

Air and enriched air nitrox differ in oxygen content; nitrox contains a higher proportion of oxygen than air. Gas composition is central to dive planning because it affects oxygen exposure and inert-gas uptake, while depth and time shape the pressure exposure. These factors make breathing gas a meaningful variable in studies of divers’ responses.

Changing the breathing gas does not isolate every possible cause of fatigue. A careful interpretation also considers the dive profile, workload, rest, sleep, individual variation and how fatigue is measured. The article’s subject therefore sits at the intersection of gas physiology and the wider study of post-dive condition.

How can fatigue be assessed?

Fatigue can be approached through a diver’s own report, a task-based assessment or a combination of measures. Self-reports describe perceived tiredness; performance tasks can examine particular functions, such as attention or reaction. Each method captures a different aspect, so the choice of measure shapes the question a study can answer.

When reading research on this topic, it helps to distinguish a subjective feeling from an objectively measured change in task performance. Neither alone describes every practical consequence. Timing matters too: an assessment immediately after a dive addresses a different point in recovery than one made later.

Exposure: a dry chamber dive to 18 msw.
Breathing gases: air and enriched air nitrox.
Outcome of interest: fatigue after the dive, which may be assessed in more than one way.
Interpretive context: pressure exposure is not the same as the full physical and environmental demands of open water.

Why does this research question matter beyond the chamber?

Post-dive fatigue is relevant to recreational and occupational divers, scientific teams, diving physicians and hyperbaric clinicians. It is one part of the broader assessment of how people respond to diving, alongside decompression, oxygen exposure, cognitive function and recovery. These topics are related, but fatigue by itself does not establish a diagnosis or identify a specific cause.

Chamber research offers a way to examine selected exposures under controlled conditions; field observations address the complexity of actual dives. Together, these approaches help define which variables deserve attention and where findings may apply. Anyone with persistent or concerning symptoms after diving should seek assessment from a diving-medicine physician.

Frequently asked questions

What does 18 msw mean?

It means 18 metres of seawater, a way of expressing depth-related pressure in diving. In this article’s subject, the exposure takes place in a dry chamber rather than underwater.

What is enriched air nitrox?

Enriched air nitrox is a breathing gas with a higher oxygen proportion than air. Its use requires attention to oxygen exposure and to the dive conditions.

Does fatigue mean decompression illness?

No. Fatigue is a nonspecific experience and does not, by itself, diagnose decompression illness or explain its cause. Symptoms after diving that concern you warrant prompt advice from a diving-medicine physician.

Citation details

Title: Measurement of fatigue following 18 msw dry chamber dives breathing air or enriched air nitrox
Authors: Harris RJ, Doolette DJ, Wilkinson DC, Williams DJ
Year: 2003
Published in: Undersea Hyperb Med 30(4)
Identifiers: PMID 14756231
Record type: Journal article
Repository record: Rubicon Research Repository, handle 123456789/3975

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.