The advantages of diving with Nitrox over air

ByNiels-Peter Brændeskov

Not so many years ago, enriched air nitrox (EANx) was something only advanced technical divers used. Today, it is widespread among recreational divers – in fact, PADI Enriched Air (Nitrox) Diver PADI's most popular specialty course.

Here you will get an overview of what it takes to become an Enriched Air (Nitrox) Diver, the advantages and disadvantages of diving with nitrox rather than regular air, and what it means for us as divers.

What is Nitrox?

We humans are used to breathing an air mixture that consists of approximately 79% nitrogen and 21% oxygen. Technically, any mixture of nitrogen and oxygen is nitrox – including the air you are breathing right now.

In recreational diving, the term is used nitrox (or Enriched Air / EANx) typically refers to gas mixtures with 32% (EANx32) or 36% (EANx36) oxygen. More oxygen means less nitrogen – and that offers some significant benefits.

Can you dive longer with Nitrox?

As you learned in the PADI Open Water Diver course, nitrogen uptake is one of the factors that limits how long and how deep we can dive. Nitrox allows you to:

  • Extend bottom time
  • Shorten surface intervals
  • Dive deeper on repeat dives
  • Increase safety margins if you dive nitrox but follow air profiles

Many divers use nitrox precisely to reduce their nitrogen uptake, even when adhering to air no-stop limits. It is an effective way to dive more conservatively and increase personal safety.

Is Nitrox worth it?

If you want to stay further down and get back in the water faster, then yes – it’s definitely worth getting an EANx certificate. You’ll have more time to take pictures, greet sea turtles and explore the underwater world.

Even on a single dive deeper than 15 meters, nitrox can give you benefits.

An example:

  • A dive to 21 meters on air provides a non-stop time of 40 minutes.
  • The same dive with 32% nitrox gives 60 minutes no-stop time.

Det er 20 minutters ekstra undervandstid – medmindre du løber tør for gas før det, selvfølgelig.

Nitrox and repetitive dives

Many divers wait far too long to try nitrox – often they only discover the benefits when they are in the middle of a diving holiday.

Imagine this:

You are on day two of your diving trip. Your first dive was deep – under 30 meters. After a relaxing surface break, you are looking forward to your next dive: a famous wreck.

The briefing reminds the air divers to keep an eye on their no-stop time. During the dive, you must turn around before the nitrox divers. You watch enviously as they continue around the wreck, following a school of rays and finding “treasures” you don’t get to see.

If you are planning a liveaboard or multi-day diving holiday, do yourself a favor and take the nitrox course. You will get significantly more out of your dives.

Advantages and disadvantages of diving with Nitrox

Benefits

  • Longer bottom time or shorter surface intervals
  • Better options on repeat dives
  • Greater safety margins if you follow the air's no-stop limits
  • Many divers experience less fatigue after nitrox dives (not scientifically proven)

Disadvantages

  • Price Nitrox fills are often more expensive than air
  • Depth limitations: To avoid oxygen toxicity, the maximum depth is lower than with air.
  • Availability: Not all dive centers offer nitrox
  • Equipment: You must use a cylinder approved for nitrox.

Also remember that nitrox does not change how much you consumer of your gas. If you use a lot of air, your dives can still be short – so it pays to work on your gas economy.

What does the PADI Enriched Air Diver course include?

The course consists of three parts:

  1. Theory (eLearning)
  2. Practical exercises
  3. Two optional open-water dives

1. Theory (eLearning)

You will learn, among other things:

  • What nitrox is and why it gives longer bottom time
  • Equipment requirements and correct labeling of nitrox cylinders
  • What oxygen toxicity is and how to avoid it
  • How to set your dive computer for nitrox
  • How to plan nitrox dives and calculate max depths
  • Risks of nitrox and how to manage them

2. Practical exercises

You train, among other things:

  • Nitrox analyzer calibration
  • Analysis and correct labeling of your cylinder
  • Filling out the enriched air log
  • Setting the dive computer for nitrox
  • Logging nitrox dives

3. Open-water dive (optional)

Although optional, they are highly recommended. It gives you confidence and experience to do your first nitrox dives with an instructor.

More good reasons to take the Nitrox course

  • You get to know your dive computer better
  • You will gain a deeper understanding of diving physiology – important if you want to be a Divemaster or Instructor
  • Nitrox certification is a requirement for technical courses
  • Some liveaboards and dive centers require nitrox certification
  • It is a step towards Master Scuba Diver

Get started with your Nitrox certificate

It only takes a few hours to get certified. You can do most of it from home via PADI eLearning. You then meet briefly with an instructor to practice using the analyzer and go over procedures – and you have the option to do two nitrox dives.

The course has been modernized so that you no longer have to juggle multiple tables. Today, almost everything is done via dive computer.

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