Nitrox?

[OMyMyOHellYes]

This theory has been thoroughly debunked.

What protocol was used in debunking the theory that Ross' dad felt better after EANx dives? Over what period of time were the studies conducted? How much diving, with and without EANx, and for what times and depths, did Ross' dad devote to testing whether he felt better after his EANx dives?

 

[OMyMyOHellYes]

So I'm just an occasional diver and as I said am reluctant spending a lot of time, energy and money getting certifications and equipment i probably will never use or need, except maybe a dive computer.

Time and energy invested for EANx cert is minimal. Maybe an hour of classroom. Other than having a chance to dive, an in-water EANx training dive (IMNSHO) is pointless: you learn how to do the pre-dive stuff and dive like any other dive, but with different NDT and surface intervals. Your computer will tell you what those are.

My course summary (or at least my takeaways):
Discuss how pressure builds with each 10M of water. Understand a very minimal amount of theory as to percentage of O2 in breathing gas and how that relates to depth and O2 limits and consequences like O2 toxicity. You'll hear things like PPO 1.4 and 1.6 and know one is the limit (don't go past) and the other is the hard limit (deadly bad things can happen really quick if you go past). Work through how the numbers run through the formula and establish max operating depth (MOD) - this was all just to conceptualize - you probably will never see those calculations again. Your computer will tell you or there's likely a chart at the fill station that says your "MOD at XX% O2 is YYY".

The operational part of the course entails how to test O2 concentrations using an analyzer (easy) - in recreational environments to verify the MOD from a chart on the wall and how to set up your computer (so may need the computer first)

Summary: EANx Rec = know how to test O2 concentration, verify/setup dive computer for O2 concentration, label tanks, dive.

It's good stuff to know in any case. And it's a one-time expense. And you get more plastic. I don't particularly think more plastic's a good thing.

 

[Blackcrusader]

If your dives are being ended because of hitting NDL, then nitrox is going to help. If your dives are being ended because you hit a gas limit then it won't extend your bottom times. Only you know from your experience which one you hit first.

There are other physiological benefits from diving nitrox without extending your bottom time that you can research on this forum as well, but specific to your question, it all depends on which limit you hit first.

Yes nitrox is good to have. ATM where I am diving they do not offer nitrox just 21% air.


On this dive ( my second dive today ) I was using 21%. If I had been using nitrox my time to NDL would have been longer but dive time the same if I kept same dive profile. As it was 3 other divers on the same dive were back on the boat and taken to shore after 50 mins as they used up their gas a lot faster. My DM and I continued and finished this dive today with 75 minute + dive time. The same dive on nitrox would have had the same dive time.

Let's say you have a dive to 30m and use nitrox. You have a longer NDL time but as you stay deeper you use more gas. So you need to ascend so as not to get too low on gas. Your total dive time may only be 45 minutes.

My dive time might be 60 minutes if I use less gas than you do

 

[Blackcrusader]

Recreational dives for cruise ship passengers never go beyond 45, maybe 50 minutes on the very outside. Usually they are 35-40 mins.
At this stage in my experience I'm using up gas pretty fast, usually get low at about 35 mins.

I'm 185cm tall, a bit portly at 135kg, or one could say better insulated. So far I have done around 25 dives in the 11 days. The water temperature has been 26c or 27c and divers with me are getting cold. Had to insist my DM use a thicker wetsuit so he can keep with with my dive times lol Dived with this same DM for several years now. If we are doing 3 dives a day then average time is 70 minutes or more. Some dives are inter island day trips but when only two dives its because bad weather and coast guard telling dive ops they cannot do inter island trips.

If two dives 90 mins plus 80 mins on second dive. Max Depths are listed there as well.

 

[Blackcrusader]

25 hours under water in a week is simply not practical without NITROX.

I do it quite often. Some surface intervals are 90 or 120 mins though.

 

[Blackcrusader]

I cannot say I agree with this myself, I certainly feel less tired after diving on Nitrox, especially over 24 metres. Most people I dive with also think this. Personally I cannot see how anyone can disprove this claim, it is highly objective.

I Just accept what people tell me. I often do 35 - 40 dives in a 12 diving day trip. Some places don't offer nitrox some do. I feel no different with nitrox than without. However, I do eat well, keep myself hydrated and am normally asleep by 10:30pm and get in a solid 8 hours of sleep. Some people go party till 4am then come to dive shop at 8am for inter island trip spouting off how tired the diving makes them feel. lol

 

[Blackcrusader]

I appreciate the feedback. So far every dive I've done has been pretty simple and the DMs have always looked after the "old, new guy".

Last November I was in Bohol where I dive from time to time. My usual DM was not available for my dive trip so was assigned another. On several dives that old guy being me had to keep tab on the DM as the DM was the one low on air when I had near half a tank. You do not know if your DM got certified as DM the day before you dived with them. Do not assume that the title DM means the diver is really experienced.

Now for my SPG ( not suggesting you get the same unless you like spending money ) it shows depth, max depth, time, water temp, air and Range. Range means from the point of time on a dive to 50 bar or 750 psi. So lets say you want to make sure you can do a dive of 60 minutes and have 750 psi at 60 minutes. You look at the time dived already, and the range showing. Add the two together.


So on this dive after 31 minutes I have used about 30% of a tank of air. Range now shows that if I stay at 8m depth I can do another 67 minutes to 50 bar / 750 psi. This is a standard 80 cubic foot AL tank. So on this dive I could do another 90 minute dive to 50 bar / 750psi

 

[Eric Sedletzky]

Examples of fatiguing "narcotic" effects: alcohol, marijuana, morphine, heroin, hydrocodone, etc.
Basically, all the "depressant drugs". They all often make you feel tired or sleepy.

Also, the times that I have experience nitrogen narcosis specifically, I found experience highly fatiguing. So anything that reduces that nitrogen narcosis would also likely reduce the fatigue.

All of those drugs you listed are foreign substances that after entering the body need to be metabolized and processed/removed by the liver etc. and in many cases inflict damage upon the organs/tissues/ brain.
Atmospheric gases clear without trace and the narcotic affects are temporary that do not cause any permanent damage. However dissolved gases in solution that come out of solution too rapidly CAN cause nerve damage and subclinical DCS and yes, can lead to fatigue. But drug fatigue and gas caused fatigue are two entirely different things in how they cause fatigue.
BTW, if you want to ingest a foreign substance that most closely mimics the effects of diving narcosis, nitrous oxide is your best bet.

 

[dmaziuk]

Examples of fatiguing "narcotic" effects: alcohol, marijuana, morphine, heroin, hydrocodone, etc.
Basically, all the "depressant drugs". They all often make you feel tired or sleepy.

This may come as a shock, but... are you sure you're doing them right?

 

[gamon]

I cannot say I agree with this myself, I certainly feel less tired after diving on Nitrox, especially over 24 metres. Most people I dive with also think this. Personally I cannot see how anyone can disprove this claim, it is highly objective.

No, in fact your claim, as well as everyone else who says they feel better after diving Nitrox is completely subjective.

This is exactly why medical, clinical, and scientific studies when properly done all account for the placebo effect- because large numbers of people are convinced that they feel better, and/or actually improve when taking a pill that they believe will help them when in fact it 's an inert substance used as a "control".