Which approach helps prevent nitrogen narcosis during diving?

• A. Use a gas mix with less nitrogen
• B. Dive deeper to acclimate
• C. Hold breath during descent
• D. Increase nitrogen in the mix

Answer: (A)

Nitrogen narcosis happens because, as you go deeper, the partial pressure of nitrogen in your breathing gas increases and can depress the central nervous system. The way to prevent it is to lower how much nitrogen you’re breathing at depth, which reduces its narcotic effect. Using a gas mix with less nitrogen achieves exactly that by replacing part of the nitrogen with other gases or with oxygen, so the same depth results in a lower nitrogen partial pressure. In recreational diving this is often done with nitrox, which has a higher oxygen fraction and a correspondingly lower nitrogen fraction, cutting narcosis risk at common recreational depths. It’s also essential to monitor oxygen exposure, keeping the partial pressure of oxygen within safe limits. The other options don’t help: diving deeper increases nitrogen pressure and worsens narcosis, holding your breath is dangerous and won’t prevent narcosis, and increasing nitrogen in the mix would raise the narcotic load rather than reduce it.