Diving on enriched air nitrox, often called "nitrox," is increasingly popular among recreational divers. But what is it? Nitrox is a mixture of nitrogen and oxygen, with a higher oxygen percentage (usually between 28-36%) than regular atmospheric air (or the air we breathe from a normal scuba tank) which contains 21% oxygen, and about 79% nitrogen. Choosing nitrox over normal air has several advantages, particularly for those looking to extend their bottom time, reduce post-dive fatigue, and enhance overall safety.
1. Extended Bottom Time
One of the primary reasons divers choose nitrox is for the extended bottom time it allows. Because nitrox has a reduced nitrogen concentration compared to regular air, it slows the buildup of nitrogen in a diver's tissues. When diving with a lower nitrogen mix, you can stay at depth longer without risking decompression sickness, which results from too much nitrogen in the body. This is particularly beneficial for those diving multiple times a day or conducting deep dives, as the accumulated nitrogen can be managed more effectively.
For example, on a typical recreational dive to 18 meters (60 feet), divers using a 32% nitrox blend could stay underwater nearly twice as long as those using regular air, according to standard dive tables. This extended bottom time means more opportunity to explore dive sites, observe marine life, and experience the underwater environment. However you must be careful! As you will learn in the Nitrox Course, you will have a different 'maximum operating depth' due to the increased Oxygen content, so its very important to define your diving limits, while you also get to enjoy the benefits of longer bottom (NDL) time.
2. Reduced Post-Dive Fatigue
Many divers report feeling less tired after diving on nitrox compared to regular air, especially when performing multiple dives in a day. While the exact reason for this is still debated, a common theory is that the lower nitrogen absorption from nitrox reduces the body’s workload in processing excess nitrogen after the dive. In my humble opinion, I agree that it makes you 'feel better'! However, I know some very experienced divers who feel no difference.
Less nitrogen absorption could mean the body doesn’t have to work as hard to expel it, potentially reducing post-dive lethargy. For those on dive vacations or diving consecutive days, using nitrox may mean feeling more energized and ready to dive again. Many divers about a liveaboard (like our Deep Andaman Queen) will prefer to use enriched air.
3. Added Safety Margin
Diving with nitrox can provide an added safety margin, as the lower nitrogen load in your system reduces the risk of decompression sickness. This is especially advantageous for older divers, those with certain health conditions, or those who want an extra layer of protection. However, it’s essential to remember that while nitrox offers a safety benefit, it is not a substitute for proper diving practices. And again, you must be very aware that the increased oxygen content will mean that your maximum depth is actually a bit higher than on normal air, due to oxygen toxicity concerns. It is a great tool in the toolbox if used correctly, but for safety reasons, it requires a special license!
4. Considerations and Training Requirements
While nitrox has clear benefits, it’s not without risks. Again, with a higher oxygen concentration, there’s an increased risk of oxygen toxicity, particularly at deeper depths. Diving on nitrox requires an understanding of maximum operating depths (MOD) and the effects of breathing higher levels of oxygen underwater. To dive with nitrox safely, divers must complete a nitrox certification course that covers these principles and teaches divers how to analyze their gas mix. Dive computers that are set to your particular blend of enriched air will calculate your bottom time and your maximum operating depth, but it is vital to understand these concepts.
Conclusion
For divers looking to extend their bottom time, experience less fatigue, and gain an added safety margin, enriched air nitrox is a valuable option. With proper training, nitrox can be a great asset, especially for those diving multiple times a day. Also, it is a great introduction to technical diving, like trimix, which will add helium for non-recreational depths! While nitrox does require more planning and knowledge, the benefits can significantly enhance a diver’s experience underwater.
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