Nitrox: real benefits and common myths

Many divers feel it does, but DAN reports that objective studies have not found a reliable difference in fatigue or cognitive performance after air versus nitrox dives. Divers who feel better on nitrox are free to use it — the placebo effect simply hasn't been ruled out.

With less nitrogen in each breath you have three options: stay longer within no-decompression limits, take shorter surface intervals, or dive the same profile with less decompression stress. DAN notes that if you use nitrox to stay down longer, right up to its no-decompression limit, your decompression stress is comparable to diving air to the air limit — so it recommends using nitrox mainly to reduce decompression stress.

It's the reason nitrox has a maximum operating depth. In a DAN study of nearly 400 U.S. recreational diving deaths over ten years, only one of the 55 nitrox fatalities was considered likely due to an oxygen-toxicity seizure — on a technical dive to about 49 metres, deeper than the maximum operating depth for EAN32. Exceeding the gas's maximum operating depth raises the risk of oxygen toxicity, but staying within limits does not eliminate it: exercise, cold, medication and individual susceptibility also matter. Analyse each tank and mark its oxygen percentage and maximum operating depth.

Take an Enriched Air Nitrox course (PADI, SSI, SDI or TDI) — usually half a day to a day. You learn to analyse your gas, set your computer and respect the maximum depth. On our boats nitrox is €8 a tank for certified divers.