Behavioral Effects of Increased CO2 Load in Divers

5 min read · 22 April 2026

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Behavioral effects of increased CO2 load in divers is a 1990 publication by Henning and colleagues on carbon dioxide exposure and behavior in diving. Its subject matters because breathing-gas conditions and exertion can influence how a diver thinks and acts, with consequences for judgment, task performance and safety underwater.

Why does carbon dioxide matter underwater?

Carbon dioxide (CO2) is produced by the body’s metabolism and normally removed through breathing. Its concentration in the body depends on both production and ventilation: when a diver’s breathing does not clear CO2 effectively, the body’s CO2 load can rise.

Underwater, breathing is shaped by equipment, the surrounding pressure, workload and the resistance of the breathing system. Exertion raises metabolic demand, while a diver may have limited ability to change pace or posture. These factors make CO2 a relevant part of understanding the interaction between physiology and performance during a dive.

What does a behavioral-effects question involve?

Behavior is broader than a visible mistake. In diving research, it can refer to how a person attends to information, makes decisions, carries out tasks or responds to changing conditions. Examining behavior alongside a physiological exposure helps frame whether altered breathing-gas conditions could matter for practical activities underwater.

The title places the publication at the intersection of respiratory physiology and human performance. It signals an interest in increased CO2 load as a condition under consideration and in behavioral effects as the topic of study; it does not, by itself, specify particular outcomes or how they were assessed.

CO2 production: the carbon dioxide generated as the body uses energy.
Ventilation: movement of air or breathing gas that supports oxygen uptake and CO2 removal.
Work of breathing: the effort required to move gas through the respiratory system and diving equipment.
Behavioral performance: attention, judgment and task execution in the conditions being examined.

Why is this important for divers and clinicians?

A diver may need to monitor instruments, manage equipment, communicate and respond to hazards while also controlling buoyancy and breathing. Anything that interferes with attention or decision-making could complicate these tasks. For this reason, behavioral questions are relevant not only to individual divers but also to dive planning, equipment evaluation and clinical understanding of incidents.

Diving physicians and hyperbaric clinicians consider respiratory symptoms and environmental or equipment factors in context. CO2-related concerns can overlap with other sources of discomfort or impaired performance, so the broader task is to distinguish contributing factors rather than assume a single explanation. Questions about a person’s fitness to dive or symptoms require assessment by a diving-medicine physician.

How does this subject fit into diving research?

Diving research brings together gas physics, respiratory physiology, equipment design and human performance. Studies of breathing-gas exposure and behavior sit within that wider effort: they address how the conditions of immersion and breathing interact with the diver’s capacity to perform tasks. The 1990 publication’s title and its appearance in Undersea Biomedical Research place it within the established biomedical study of diving.

The subject also connects to practical questions about breathing-system resistance, workload and safe work underwater. Research in this area can help define which physiological variables merit attention when evaluating performance, without reducing every behavioral change to one cause. It is one part of a larger picture that includes the diver, the task, the environment and the equipment.

What should readers take from the topic?

Increased CO2 load is important to diving because the body’s ability to eliminate carbon dioxide depends on ventilation, while underwater breathing and workload can impose specific demands. Behavioral effects are a consequential research question: safe diving depends on more than adequate gas supply, and also requires reliable attention and action.

Henning and colleagues’ publication is a historical contribution to this subject, framed around CO2 load and diver behavior. Readers can use that framing to understand why diving medicine considers respiratory physiology alongside human performance, while treating clinical concerns as matters for qualified medical assessment.

Frequently asked questions

What is CO2 load?

CO2 load describes the carbon dioxide present in the body as it is produced by metabolism and removed through breathing. A balance between production and ventilation is important for normal gas exchange.

Why study behavior in relation to breathing?

Divers must maintain attention, make decisions and perform tasks while managing equipment and the underwater environment. Studying behavior alongside respiratory conditions helps frame how physiology may be relevant to those demands.

Who should assess a diving-related medical concern?

A diving-medicine physician should assess symptoms, fitness-to-dive questions or concerns about breathing and performance. General information cannot replace an individual medical evaluation.

Citation details

Title: Behavioral effects of increased CO2 load in divers
Authors: Henning, RA; Sauter, SL; Lanphier, EH; Reddan, WG
Year: 1990
Published in: Undersea Biomedical Research 1990 Mar;17(2):109-20
Identifiers: PMID 2108518
Repository record: Rubicon Research Repository, handle 123456789/2540

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.