Decompression Tables: Use, Limits and Dive Planning

By Rubicon Foundation editorial team

6 min read · 1 November 2026

Decompression tables turn a planned dive profile into limits for depth, time and ascent, helping divers manage the risk of decompression sickness. Their research area asks how well those rules represent gas exchange in the body, how divers can apply them safely, and where a table’s assumptions meet the variability of real dives.

What does a decompression table represent?

When you breathe compressed gas underwater, the increased pressure raises the partial pressures of the gases in your breathing mix. Inert gases, principally nitrogen in ordinary air, dissolve into body tissues. During ascent, pressure falls and those gases move back towards the lungs for elimination.

A decompression table is a planning model for that process. It organizes permitted depth and bottom-time combinations and, where required, staged ascents or surface intervals. The table does not measure gas in a diver’s tissues; it applies a set of assumptions to a planned profile.

Those assumptions matter because tissues do not all take up or release inert gas at the same rate. A model may represent this complexity with theoretical tissue compartments, each assigned a different response to pressure changes. The compartments are calculation tools, not literal anatomical structures.

How are table rules developed and assessed?

Research on decompression tables combines physiology, mathematical modelling and observation. Models estimate inert-gas uptake and elimination across a dive profile, while experimental and operational evidence can be used to examine how their predictions perform. Researchers also consider how divers follow the prescribed depth, time and ascent sequence.

One central question is how conservative a rule should be. A more cautious limit may reduce exposure to a modelled decompression burden, but conservatism is not a guarantee against decompression sickness. The risk depends on the profile and on individual and environmental factors that a table cannot fully represent.

Depth and duration: the pressure exposure that shapes inert-gas loading.
Ascent rate and stops: how pressure is reduced and time is allowed for gas elimination.
Repetitive dives: how residual inert gas from an earlier dive affects the next plan.
Model assumptions: how calculated tissue responses translate into practical limits.

Table design is therefore not just a matter of solving equations. It also involves deciding which profiles to evaluate, how to interpret evidence, and how to express a rule clearly enough to use underwater.

Why can a table not predict every diver’s outcome?

A table gives a standardized plan, but divers differ in physiology and in how a dive unfolds. Actual depth and time may depart from the planned profile; exertion, cold, and other conditions can also affect the context in which decompression occurs. A printed limit cannot account precisely for every combination.

Decompression sickness is a clinical condition, not simply a violation of a table. Symptoms can occur after a dive that appeared to follow a recognized schedule, while compliance does not establish that a diver is free of risk. Suspected decompression illness needs prompt assessment by an appropriate diving-medicine service.

These limitations make clear planning and disciplined execution important. Divers need to understand which table they are using, its depth and gas assumptions, and how it handles repetitive dives; changing those conditions can make its guidance inapplicable.

How do tables fit alongside computers and dive medicine?

Decompression tables belong to a wider effort to translate gas kinetics into usable dive procedures. Dive computers address a related planning problem by tracking a changing profile during the dive, while tables provide a pre-planned framework. Neither removes the uncertainty inherent in modelling decompression.

Comparisons between planned and actual profiles raise practical questions: whether the chosen model fits the dive, how a diver responds to a changing schedule, and whether different calculation approaches give meaningfully different guidance. These questions connect equipment, operational safety and decompression physiology.

For physicians and hyperbaric clinicians, decompression planning is relevant to understanding the exposure preceding a suspected illness, but a table alone does not diagnose or rule out a medical problem. Treatment decisions belong with clinicians experienced in diving medicine and hyperbaric care.

What should a diver check before relying on a table?

Start with the table’s intended use and confirm that the breathing gas, depth range and dive pattern match its assumptions. Check how it defines bottom time, ascent procedures, repetitive-dive allowances and any required surface interval. If an element is unclear, consult the table’s official instructions rather than improvising.

Use one coherent planning method and make sure everyone in the team understands the schedule and contingencies. A table is a decision aid, not a substitute for training, an appropriate dive plan or medical assessment when symptoms arise.

Frequently asked questions

Do decompression tables guarantee a safe dive?

No. They provide structured limits based on a model and specified assumptions; they cannot account for every diver or every condition, and following a schedule does not eliminate risk.

Why do tables include different tissue compartments?

Compartments represent different rates of inert-gas uptake and release in a mathematical model. They help calculate how a pressure exposure may affect decompression requirements, but they are not literal body parts.

When should a diver seek medical advice after a dive?

Seek prompt assessment from a diving-medicine physician or appropriate emergency service if symptoms after diving raise concern for decompression illness. A table cannot diagnose or exclude the condition.

An original research-library explainer written by the Rubicon editors. It is not a summary of a specific publication.