Nitrox Question

[DevonDiver]

ALL Nitrox classes should require dives to go along with the classwork. If you have not dove breathing Nitrox then you should not receive a Nitrox certification card.

Actually, it is that agencies that do not require dives with the certification. To add dives to a course is the perogative of the individual dive center.

Given that analysis, dive planning, procedures for obtaining and marking cylinders are all covered on the course (practical and theory).... what 'skills' are left to do on the actual dive? Stick to the MOD. That is it.

Any certified diver should be able to stick to a MOD. After, we learn this 'skill' from Day 1 of an OW course. We practice it on every dive that we plan and conduct. Our very certification levels impose MODs on us (OW @ 18m, AOW @ 30m etc).

Diving Nitrox is NOTHING like diving technical Trimix...as there are no gas switches to worry about, no worry of falling below safe P02 levels and much less dve planning,

For me, Nitrox only really comes into great effect when I am diving with doubles...or doing 2+ deep dives a day (as the benefit of decreased N uptake is more evident when planning repetative dives).

 

[Walter]

Actually, it is that agencies that do not require dives with the certification.

At least one does.

 

[DaleC]

I am curious as to why the breathing of a higher O2 content would have no real effect on a diver. If I am using EAN32% I am breathing 50% more O2 that air. Common sense tells me that an increased O2 level = increased physical performance and/or reduced stress and/or faster recovery but... even as I write this I can think of a reason that might negate its benefit.

Most cases of benefit from increasing the breathable O2% level deal with situations where tissue is O2 starved, such as high altitude mountaineering or trauma/illness resulting in reduced cellular perfusion. Increasing the O2% benefits the body as there is an O2 "defecit" that needs to be filled.

But what about a healthy body in a non stressful dive situation? The question might be whether or not recreational diving causes a diver to exert him/herself to the point where they build an O2 defecit in the first place. If the body already has a surplus of O2 at an atmospheric rate of 21%, increasing the % will not "add" any usable O2 to the diver.

Hummm.... 5 minutes ago I had the answers; now all I have is more questions. Now I have to do some more research. Curse you, Nitrox gods!!!

 

[farsidefan1]

Thanks for including the study. It certainly gives me something to think about. I'm not sure I'm buying the subconcious part but again, thanks for the info and I certainly can't completely dismiss the possibility. All I can say for certain is I noticed a difference, as you say, placebo or not it seems to work for me. PS, I hope reading the study outline doesn't remove the effect if it has been a placebo. lol Thanks again

Excellent point! On the other hand, you might not consciously remember having heard about nitrox reducing fatigue, but do remember hearing about it subconsciously. You've also probably seen football players breathing oxygen on the sideline. It's quite easy to connect that with nitrox. The anticipation doesn't have to be conscious. By the way, oxygen has not been shown to be of any benefit to football players either.

As for single dives vs several dives, some agree with you, others feel better after one dive, others feel no difference at all after a single dive or multiple dives.

Double blind study.

As I said before, There is room for more study, but until that happens, there's no reason to believe it is anything other than a placebo. On the other hand, if it works for you, it works, placebo or not.

 

[Walter]

And there is still room for lots more study. Future studies might show us it is not a placebo. Time should tell.

 

[bleeb]

But what about a healthy body in a non stressful dive situation? The question might be whether or not recreational diving causes a diver to exert him/herself to the point where they build an O2 defecit in the first place. If the body already has a surplus of O2 at an atmospheric rate of 21%, increasing the % will not "add" any usable O2 to the diver.

Your guess, if I may call it that, is indeed correct. Even at sea level, the human body comes nowhere near using up the O2 in breathing air. IIRC, some people under resting conditions may be exhaling as high as 19% O2, and at the other extreme, for someone in reasonably decent cardio condition working hard, O2 consumption maxes out at 4.5-5%, i.e. exhaling 16% O2.

For example, if you're breathing 32% and working hard, at 1 atm depth the stuff you're bubbling away is still at least 30%.

 

[DaleC]

Thanks Bleeb.
This is a very interesting topic to me as I do notice a difference between EAN and air. Most notably feeling fresher after repetitive dives. The Ocean is about a 1-1.5 hr commute for me and when I dive EAN I feel awake on the drive home while, on air, I have to buy a coffee and slap myself silly to keep from nodding off (scary thought for the other drivers eh ). I dive weekly so I notice this effect on a regular basis.
I'm going to look at other sports/pastimes to see if increasing the O2% is advocated to increase performance/recovery or not.

 

[siikik]

SSI requires a dive,,take the class and it can be taken as one of the OW cert dives

SSI does not require a dive... perhaps you shop did. Kudos to them for going above and beyond! Wish my LDS did that.

But as far as requiring a dive, if you can accurately plan the dive and understand the material, diving Nitrox only gets you another dive... IMHO that is. You can't tell you're breathing Nitrox.

NAUI also does not require a dive, but, as you pointed out, you are allowed to use Nitrox for your OW dives as long as you passed the academics.

Thanks Bleeb.
This is a very interesting topic to me as I do notice a difference between EAN and air. Most notably feeling fresher after repetitive dives. The Ocean is about a 1-1.5 hr commute for me and when I dive EAN I feel awake on the drive home while, on air, I have to buy a coffee and slap myself silly to keep from nodding off (scary thought for the other drivers eh ). I dive weekly so I notice this effect on a regular basis.
I'm going to look at other sports/pastimes to see if increasing the O2% is advocated to increase performance/recovery or not.

While it's nice to think extra oxygen will do this, it simply doesn't accumulate in your body like nitrogen does. Your muscles are likely recuperating faster given they are getting more oxygen during use. No doubt EAN has a positive effect, but I have not noticed this post-dive.



Ken

 

[ScubaDocER]

NAUI also does not require a dive, but, as you pointed out, you are allowed to use Nitrox for your OW dives as long as you passed the academics.

This is not true. The following is a quote from the NAUI S&P.

"SKILL REQUIREMENTS
For the EANx Diver certification at least two dives are to be
planed and safely executed using EANx, one of which is to be
a repetitive dive.
The student is to analyze his or her own breathing mixture."

It is true however that you can use Nitrox as part of your OW dive.

"This course is to provide the diver with the information
necessary to utilize EANx as a breathing medium. The
course may be taught as a stand-alone specialty course to
certified divers or the knowledge and skills training may be
integrated into other NAUI certification courses including
the NAUI Scuba Diver Course."

 

[DaleC]

While it's nice to think extra oxygen will do this, it simply doesn't accumulate in your body like nitrogen does. Your muscles are likely recuperating faster given they are getting more oxygen during use. No doubt EAN has a positive effect, but I have not noticed this post-dive.
Ken

I was not thinking that I was still experiencing the effects of EAN post dive but rather, that the effects of EAN while diving left me less fatigued afterwards. Now I question whether the body can utilize the additional O2 or not. I don't know the answer.

I imagine an easy way to determine this would be to wear an O2 satuation monitor and see if the sat rate drops while diving air. I'm sure someone has done this before. If the sat rate drops then there would be a strong case for EAN benefit. If the sat rate did not drop then it would have to be demonstrated that the body benefits from O2 super saturation during normal recreational diving conditions.