In controlling the risk of DCS, what is the ideal Nitrox mix for deeper dives?

Choosing a lower oxygen concentration for deeper dives is the ideal Nitrox mix to control the risk of decompresssion sickness (DCS). This is because deeper dives typically involve longer exposure to higher pressures, which increases the absorption of nitrogen in the body. By using a Nitrox mix with a lower oxygen concentration, the overall percentage of nitrogen is also reduced.

When divers use a lower oxygen concentration, they minimize nitrogen loading—which is integral to reducing the risk of DCS. This is particularly important because nitrogen is the gas that can lead to bubbles forming in the body during ascent, which is the primary cause of DCS. By selecting a mix that balances the need for oxygen (given the increased depth) with the imperative to minimize nitrogen intake, divers can optimize their safety.

Additional considerations are the risks associated with higher oxygen concentrations at greater depths, where oxygen toxicity becomes a concern, and why standard air mixtures are less ideal for deeper dives due to their higher nitrogen content. Using pure oxygen at depth is contraindicated as it can lead to toxicity and other complications. Thus, opting for a lower oxygen concentration in a Nitrox mix serves to enhance safety during deeper dive excursions.