What diving condition requires cautious adjustment of the EANx mix?

Cautious adjustment of the EANx (Enriched Air Nitrox) mix is particularly important in cold water conditions because cooler temperatures can lead to increased gas density. This increased density affects how gases are absorbed and metabolized by the body during a dive.

As water temperature drops, the solubility of gases changes, leading to variations in partial pressures and potentially altering the nitrogen and oxygen absorption rates. In cold conditions, diver physiology can also respond differently, with more concentrated gas mixtures impacting the risk of oxygen toxicity and decompression limits.

In colder water, divers are encouraged to carefully monitor their EANx mix to ensure it remains appropriate for the dive depth and duration, thus minimizing the risks of both nitrogen narcosis from too much nitrogen and oxygen toxicity from elevated oxygen levels at depth. This need for adjustment is less critical in warmer water, where gas absorption behaves more predictably, and visibility issues or strong currents do not directly impact gas composition and absorption concerns.