Is Nitrox helpful in Raja Ampat?

[Magrone]

Not sure about what your dive qualifications are but I am a diving and nitrox instructor
We are clearly instructed to tell students what the benefits of nitrox are and we say that the proven one is extended bottom time and as consequence reduced risk of DCI.

I Don't see how this has any relevance to the discussion. You're a dive instructor, not a scientist. Of course you tell your students what you've learned.

All others ideas like yours are theories that have no back up, if they did it would end up in the training material but to date this has not happened.

No need to repeat yourself here. I think we both know there are no studies to back up the claim that nitrox reduces fatigue in recreational diving. BUT from what our physiology tells us about how our body responds to increased oxygen during activity, there is reason enough to make an educated guess about what I experience and what the actual correlation is between Nitrox and fatigue, it just hasn't been tested in a sound study yet.

For your information there are also other theories that say that increased oxygen level actually brings more free radicals and aging and fatigue, again nobody is going in depth there as nobody wants to know if that is the case

There have been lots of studies that make a correlation between an increase in oxygen and the introduction of free radicals in the body, which, over time, can expedite the aging process, etc., but this also has little relevance to the present discussion.

The rubicon test were not only psychometric they also looked at symptoms of fatigue if you read it carefully and a test on 10 is more significant that no test. Where is one single study that proves nitrox reduces fatigue? I would love to read it.

The testing was conducted in a dry chamber, not in the ocean. 11 divers is simply too small of a sample to make any conclusions from a single study There are no tests that prove fatigue levels are decreased by Nitrox, but according to the study "it is extremely common for divers to claim less fatigue following a dive breathing EANx then they would expect for a similar air dive"... this is why the study was conducted.

Test methods used were Visual Analogues scale and MFI-20 which rely on SELF REPORT SURVEYS from the subjects. They justify this as being the best possible way of testing because fatigue is self reported. In the study no one reports feeling less fatigue. Yet in the real diving world you have an extreme amount of divers claiming less fatigue. Both are based on self reports. How does this prove anything?

You know what might be helpful? Testing people who actually claim they feel less fatigued, or testing a larger population sample in a real-world dive setting along with physiological tests like blood and tissue sampling, to cross-examine the self reports.

What's funny to me is that in the discussion section it says "It is possible these tests may not be appropriate for measuring acute change (before and after the dive). The mfi-20 has not been used in this fashion and subjects may have remembered and duplicated their pre-dive answers to some extent."

Wow, so the only real thing to conclude from this study was that it was a waste of time and money.

The psychometric (concentration) portion of the testing was consistent with previous reports of testing in a real world dive setting on regular air; no significant changes before or after the dive were found. So if there were no changes on normal air, and they know this already, why would there be changes on Nitrox? No one is claiming that nitrox improves attention and concentration skills, or "working memory". All I'm saying is that I feel less physically tired, and have more energy to keep going on a multiple dive day. Maybe they should try testing for muscle endurance/fatigue as well. It was just assumed the reported fatigue would be associated with psychological conditions instead. Which may be a contributor in some people, but how will that ever be determined if you only test 11 HEALTHY DIVERS (well, 2 with colds) IN A DRY CHAMBER?

 

[Tigerman]

Sorry Magrone, but youre trying to argue that a study of 11 people is not enough and your argument is the complete lack of other tests?

Sorry, but there is NO PROVEN EFFECT ON FATIGUE by diving nitrox, so theres no point advertising that there is.
If you believe it is an effect, good, keep believeing, keep telling people YOU FEEL there is an effect, but DO NOT state as a fact that there IS an effect when you cant prove it - it only open you to people being pissed off at you cause they dont get the effect you tell them they will..

 

[Magrone]

Hey, Tigerman

If it sounded like I was stating a fact, I apologize. This was not my intention. It has neither been proven nor dis-proven that diving on nitrox will decrease levels of fatigue when compared to diving on regular air.

To clarify the physiological aspect of the discussion, on the cellular metabolic level there is a relationship between an increase in oxygen and an increase in muscle energy in the body, similarly with the absence of oxygen during aerobic activity, there is an outcome of fatigue. This is nothing new. This is how our bodies work. If you apply this same concept to diving on nitrox; an increase in oxygen intake coupled with compression to increase tissue loading, it seems logical to assume that diving on nitrox could potentially reduce levels of fatigue. That idea is consistent with my experience.

The Rubicon study, according to interceptor121, proves "There is NO relationship between nitrox and reduced level of fatigue" It was a single study that failed to rule out many extraneous variables and used very questionable means of testing to arrive at a definitive conclusion. It really is too bad that this study received any attention at all from the dive community. There is no evidence in this study whatsoever that invalidates my claim, since both mine, and the subject's experience, are both based on self reports.

I "believe" the effects I get from an increase in oxygen at depth, the way you believe eating enough food makes your stomach full. It happens, so I pay attention to what my body tells me. This is safe diving. I have been diving with people on nitrox that go into panic attacks and have had to end their dives early.

Let's say you are on a dive and your buddy has an out-of-body experience where they feel they are going to drown underwater. They have done hundreds of dives prior to this dive and during this particular dive there was nothing threatening or out of the ordinary. The only difference between this dive and the previous hundreds of dives is the increase in oxygen in their air supply. When you are back on the boat with them and they say they prefer not to do nitrox again because they believe the nitrox may have triggered the panic attack, do you tell them, "No, the nitrox had no effect. What you felt was a placebo. The only thing nitrox does is increase your bottom time."?

What I really "believe" is that the safe diver should err on the side of their buddy's judgement.

I am simply making a report from experiences while diving on nitrox. Whether it is decreased levels of fatigue or increased levels of anxiety, I think it's foolish to state an individual's experience is false, just because some half-assed study says so.

it only open you to people being pissed off at you cause they dont get the effect you tell them they will..

I'm not selling snake oil here. There's no reason for people to get pissed off at me for what I, and A LOT of other people report.

Well, this is getting a little redundant and I'm sure the OP and everyone else following this thread is getting bored with this discussion...And frankly I have better things to do, like going to sleep. Here's the study again if anyone missed it the first time:

http://archive.rubicon-foundation.org/xmlui/bitstream/handle/123456789/3975/14756231.pdf?sequence=1

 

[Interceptor121]

The bottom line is nitrox gives you extra bottom time this is the only consideration to be done
If you read the paper of the DAN wan workshop of some years ago there are other suggestions such as
Nitrox makes you less fatigue
Improves your sex life
Improves your digestion and removes heartburn

In the end none of those should be a driver when making the decision and as an instructor I find it part oft duties to correct misleading statements

Am boarding the very same boat of the op today and will give back my findings on nitrox on not
Am planning to start on air and see how it goes

 

[Tigerman]

...
To clarify the physiological aspect of the discussion, on the cellular metabolic level there is a relationship between an increase in oxygen and an increase in muscle energy in the body, similarly with the absence of oxygen during aerobic activity, there is an outcome of fatigue. This is nothing new. This is how our bodies work. If you apply this same concept to diving on nitrox; an increase in oxygen intake coupled with compression to increase tissue loading, it seems logical to assume that diving on nitrox could potentially reduce levels of fatigue. That idea is consistent with my experience.
...

The absence of oxygen during activity is called ANaerobic, aerobic is when you have enough. However this is not neccesarilly related to the ammount of o2 you breath as much as how much o2 youre able to take up from the air you breathe, which is heavilly influenced by your cardio. The more blood your heart can pump with every beat, the less it need to work the less you need to breathe. (Lower SAC, yay)
Do remember that most of the 21% o2 we breathe even at the surface is exhaled again. Your exhalation has something like 14-17% o2 and thats why CPR works and why its possible to use rebreathers. So the question quickly becomes how much more oxygen youll be able to absorb by increasing the po2 or mixture..

In short though, the answer to the ops question is still;
Youll have more bottomn time and/or more conservative dives and you may or may not feel less fatigued - which may or may not be placebo..

 

[Interceptor121]

Just came out of the DN in the Raja Ampat itinerary total of 36 dives of which only 2 below 25 meters

dives were almost all 60 minutes and generally around the 18 meters 60 feet mark

We were the only two diving on air on the boat and we never went anywhere near 10 minutes to the decompression limits

For what concerns fatigue most of the times we were among the last people to go to sleep

 

[gekodivebali]

I would not do 4 dives a day without using nitrox on at least 2 of them.
Use the best gas for the job is what I say!

 

[Interceptor121]

I would not do 4 dives a day without using nitrox on at least 2 of them.
Use the best gas for the job is what I say!

On this boat buying individual fills is not cost effective, you either get all nitrox or stay on air

As mentioned the type of dive profiles combined with long surface intervals are perfectly fine with air and there is no real requirements of extended bottom type. I was on each dive 60 minutes in the water

 

[jcclink]

You'll have more bottom time and/or more conservative dives and you may or may not feel less fatigued - which may or may not be placebo.

The benefits of using nitrox depends more on how you dive vs where you dive. You will have more bottom time with nitrox ,but if you push your computer the dives won't be more conservative. If you feel less fatiqued using nitrox that's all that matters, placebo or not. Keep in mind how long it would take to reach the nearest operational chamber. From RA it might be Bali or Darwin. I always dive nitrox where available (which is most places these days), don't push the limits & set my computer at mix minus 2% for a little extra safety factor. If you're on a long trip doing 3-4 dives/day every little advantage helps. The extra cost of nitrox should not be a big deal, considering the cost of the trip. Just back from Indonesia (including RA) where I did 113 dives, all but 18 on nitrox.

 

[puncho]

I'm doing a 7 day liveaboard, about 17 dives in RA. I get 2 free nitrox refills a day. Would you guys recommend taking a nitrox course to take advantage of the free nitrox? Or do you think it's not necessary?