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What Are Three Benefits Of Nitrox When Scuba Diving?

Nitrox diving is a popular diving technique that offers divers several benefits over traditional air diving. Nitrox, also known as enriched air nitrox (EANx), is a breathing gas used by scuba divers that contain higher levels of oxygen, and lower levels of nitrogen, compared to regular air. This article will discuss the three benefits of nitrox as a scuba diving gas. Only the first benefit is commonly taught at novice-level diving.
  1. Reduced nitrogen absorption
  2. Increased nitrogen removal on the ascent
  3. Reduction in micro-bubbles post-dive

1. Nitrox reduces inert-gas absorption

This is the primary, sometimes only, benefits of nitrox taught in most recreational diving courses. Simply raising the fraction (%) of oxygen in a breathing mixture consequently lowers the fraction (%) of nitrogen in the mix.

Reducing the fraction of inert gas (i.e. nitrogen) in what we breathe equals a proportional reduction in the inert gas our body absorbs.

On recreational dives, nitrogen content in the breathing gas is what causes decompression sickness (DCS) in divers. Oxygen is metabolised inside the body and, therefore, cannot create damaging bubbles.

Decreasing the amount of nitrogen in the breathing gas enables significantly longer bottom time on a dive. Alternatively, it permits less nitrogen absorption over a given dive profile compared to using regular air. 

diving ascent rate nitrox

2. Nitrox accelerates nitrogen removal on ascent

In addition to absorbing less nitrogen, the second benefit of nitrox is that a higher O2% in the breathing gas also promotes faster elimination of nitrogen when the diver ascends to the surface.

This occurs because lowering the fraction (%) of inert gas being breathed causes a greater gas partial-pressure differential between the gas dissolved in the tissues and the gas breathed into the lungs.

The exact same principle of increasing gas partial-pressure differential is what technical divers utilise when “accelerating” decompression by switching to a rich oxygen mix on their shallower ascent stops.

In short, one of the major benefits of nitrox is that it accelerates the removal of nitrogen as you ascend to the surface, it doesn’t just slow its absorption when you are on the bottom.

3. Nitrox reduces micro-bubbles

The third benefits of nitrox is that it promotes more effective micro-emboli (micro-bubble) resolution on the ascent.

Microscopic bubbles form in ALL divers when they ascend. These bubbles aren’t big enough to cause any immediate harm and don’t produce symptoms diagnosable as decompression sickness.

However, those bubbles do stimulate the body’s immune system (which recognises the bubbles and attacks them). If there are many of these bubbles, a large immune response may cause noticeable effects on the diver once they’ve surfaced. This is because the immune system response (complement system) involves the release of histamine and then serotonin into the blood. Serotonin also happens to be a chemical precursor to melatonin; which induces sleep.

A diver with a significant amount of micro-emboli in their venous system may feel sleepy or lethargic post-dive as a result of that prior serotonin release.

This is known as “decompression stress”.

Nitrox raises the inert gas partial-pressure differential across bubble walls – and promotes more bubbles to crush in size and or dissipate entirely during ascent to the surface.

In theory, and as shown in scientific studies, nitrox is believed to reduce that decompression stress. Hence, divers who typically experience some decompression stress may feel that using nitrox makes them “less tired” after diving.

The benefits of nitrox are compelling

The three benefits of nitrox make a strong case for getting certified to use this breathing gas on your dives. Nitrox is not an expensive supplemental cost when scuba diving. In return, you will be better insulated against the risks of DCS and may perceive observable improvements in your post-dive vitality.

If you’re looking to take your diving to the next level, a nitrox course is a great option to consider. It can help you get the most out of your diving experience, improve your post-dive vitality and insulate you against DCS risks.

For more details, and references, see: Subclinical DCS, Decompression Stress and Post-Dive Fatigue

Read my other articles about Decompression Sickness (DCS)

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Andy Davis Technical Sidemount Wreck Diving Subic Bay Philippines RAID Courses Training

About The Author

Andy Davis is a RAID, PADI TecRec, ANDI, BSAC, and SSI-qualified independent technical diving instructor who specializes in teaching sidemount, trimix, and advanced wreck diving courses.

Currently residing in Subic Bay, Philippines; he has amassed more than 10,000 open-circuit and CCR dives over 30 years of diving across the globe.

He has published numerous diving magazine articles, designed courses for dive training agencies, and tests/reviews dive gear for scuba equipment manufacturers. He is currently writing a series of advanced diving books and creating a range of tech diving clothing and accessories

Prior to becoming a professional technical diving educator in 2006, Andy was a commissioned officer in the Royal Air Force and has served in Iraq, Afghanistan, Belize, and Cyprus.

Originally posted 2019-02-24 15:33:53.

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