NITROX for any and all dives?

[Wookie]

Can't argue with those results. I'm sure not having to return early and give people partial refunds more than paid for the training and oxygen costs you absorbed.

I'm also surprised to hear that boats return early, rather than order a helicopter (low flying) or coastguard rescue to come pick them up. Ordered through the customer's insurance so they deal with the bill.

The coast guard does not bill the victim, nor will they fly for most cases of the bends. They do not consider recreational diving bends to be a life threatening emergency.

 

[FinnMom]

I pay 10 euros more per year for the option of filling Nx. I generally have Nx in my tanks; something like 25-28% O2 (often better referred to as slitrox).

Most of my local dives are less than 13m. If I'm not going deeper than 15m, I generally just dive air settings. If I might be diving to 30 even 40m, I still use something like 25%. Using Nx on air settings is just a tiny something extra for a not-young diver.

I very much prefer Nx on a liveaboard where we are making 4 dives/day for 6+ days. I don't appreciate paying a lot extra for it though.

 

[Bob DBF]

By having a large sample population, evenly distributed between sex, age, physical fitness level, race, etc., you would get the best data, but you would want to make sure they are all experiencing the same dive, which means sitting in a chamber as it pressurizes to 60 feet.

The only problem is that you are not actually diving when you are sitting in a chamber.


Bob

 

[kelemvor]

I know I've never sat on a bench the whole time when I've gone diving...

 

[kmarks]

The only problem is that you are not actually diving when you are sitting in a chamber.


Bob

Then maybe they should put the test subjects into a pressurized water tank that simulates an underwater environment at 60 feet. You cannot get repeatable testing conditions even by putting the same people in the water at the same place repeatedly in the ocean. It would never be more than anecdotal.

 

[tursiops]

That's not a flaw, that controlling for variables. If you put everybody on a liveaboard and tell them to go dive, some people are going to bounce up and down from 60 to 40 feet the whole dive, some are going to kick, some are going to float, and your data will be meaningless. When doing a scientific study, you can only get meaningful data when you change one variable at a time. By having a large sample population, evenly distributed between sex, age, physical fitness level, race, etc., you would get the best data, but you would want to make sure they are all experiencing the same dive, which means sitting in a chamber as it pressurizes to 60 feet.

You are arguing for pure, experimental science. Sometimes that is the best approach. Sometimes it sucks. This is more in the realm of epidemiology.....make lots of observations of lots of divers in lots of situations, and tease out the commonalities and differences. Epidemiology often starts with anecdotal evidence: "Hey, lots of smokers seem to have lung cancer!" then, maybe, casual science can come in and explain why. What we have here with Nitrox and "feeling less tired" is lots of anecdotal evidence, which should not be dismissed because of a narrow view of science or a disagreement on what "fatigue" means. And now that there seem to be some possible causalities, the studies could actually be done. If those existing studies had known of the possible causalities (sub-clinical micro bubbles) they have included doppler measurement, for example.

The earth is neither flat nor a sphere, but it much more like a sphere than it is flat....

 

[kmarks]

You are arguing for pure, experimental science.

As a pure, experimental scientist*, I'd like the see the study that includes: One year old male, Sprague-Dawley rats were fed a restricted diet and observed for two hours under ambient atmospheric conditions at surface before being outfitted with modified scubapro mk11/c370 regulators and towed behind a vessel at 60 feet salt water for 1 hour...

*

 

[MaxBottomtime]

What we have here with Nitrox and "feeling less tired" is lots of anecdotal evidence, which should not be dismissed because of a narrow view of science or a disagreement on what "fatigue" means.

Unfortunately we also have the power of suggestion. Many newly nitrox certified divers have already heard the anecdotes, therefore tend to expect to "feel less tired". Even with no evidence, many will believe things without experiencing them firsthand. Every nitrox thread on Scubaboard has a post where someone heard that nitrox will relieve dry throat, decrease gas consumption or be safer than air.

 

[Lorenzoid]

As an older diver, and at an added cost of only $6/tank for locals here, I figure why not use nitrox. . . .

Six bucks is a beer or more! I'm CERTAIN the beer will make me feel better than the nitrox.

 

[tursiops]

Every nitrox thread on Scubaboard has a post where someone heard that nitrox will relieve dry throat, decrease gas consumption or be safer than air.

True, but did they report less dry throat, or decreased gas consumption? (Wookie reports they were indeed safer on Nitrox....)
My point is, they may have heard/read something, but did they then experience it? the "feeling less tired" seems to be in a category by itself. Hey, I'm a trained scientist, but will readily admit that not all things are best tested experimentally until there is some sense of what the causalities might be. You are correct: it has not been proven that Nitrox makes some people feel less tired, nor has it been disproven. The anecdotal evidence is, however, tantalizing...