• Welcome to the DeeperBlue.com Forums, the largest online community dedicated to Freediving, Scuba Diving and Spearfishing. To gain full access to the DeeperBlue.com Forums you must register for a free account. As a registered member you will be able to:

    • Join over 44,280+ fellow diving enthusiasts from around the world on this forum
    • Participate in and browse from over 516,210+ posts.
    • Communicate privately with other divers from around the world.
    • Post your own photos or view from 7,441+ user submitted images.
    • All this and much more...

    You can gain access to all this absolutely free when you register for an account, so sign up today!

using ean 50 or nitrox 50 for free dive

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

john micallef

New Member
Jul 27, 2003
i would like to know if you can use nitrox 50% or ean 50 to free dive to 20 m or will oxygen toxicty or lung expansions be a risk.also are there any benifits from using 50 % oxygen mix for free diving.i think that the risk of swb will be minimized slightly givin the greater volume of oxygen in the breath hold. also i dont think that breathing compressed air from a cilinder at the surface and desending to depth and returning to surface on breath hold will cause lung expansion injury or will it??? acording to boyles law it wont .please let me know what any of you espcialy the pros think and if it is benificial to prolong apnea and less risk of swb using ean 50 or 60

Isn't freediving just all about training / tuning the body & mind to enjoy expanding your possibilities?
So why bother using nitrox?

John, we discussed this last year I believe, so you may be able to search the site for those posts.
There is no difference in the re-expansion of gasses in the lungs: that's impossible. So that's not the concern. The 2 concerns are 1- the partial pressure of O2, and 2- the massive amounts of CO2 that could be built up in the body. I don't remember the specifics, maybe Eric F will come on to clarify.
I tend to agree with Fred that freediving should be pure, but it would be interesting to do a 10 minute recreational freedive in 10 metres of water or so :)
Erik Y.
As we discussed before, the main problems with freediving on nitrox are:

1. CO2 narcosis at depth
2. CO2 blackout at depth

Because you could stay down for 5+ minutes, the CO2 you would accumulate would be ridiculous. If you limited your dive time to the same time that you would normally dive, it would be safer. Further, in theory, it would be important to hyperventilate aggressively before taking the final nitrox breath, to reduce the accumulated CO2. Eventually the CO2 level would still surpass the level of a non-hyperventilating air diver.

Eric Fattah
BC, Canada
DeeperBlue.com - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing


ISSN 1469-865X | Copyright © 1996 - 2024 deeperblue.net limited.

DeeperBlue.com is the World's Largest Community dedicated to Freediving, Scuba Diving, Ocean Advocacy and Diving Travel.

We've been dedicated to bringing you the freshest news, features and discussions from around the underwater world since 1996.