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View Full Version : whither nitrox revisited
doole November 9th, 2003, 07:43 PM Been trying to talk my lds into offering ean, and he said (yes - this is PURE hearsay) that in a "blind taste test" the divers were generally unable to identify whether or not they had been given nitrox, after a typical rec dive dive. Anyone know if there's any truth to this? 5615mike November 9th, 2003, 08:25 PM That all depends on the depth and length of the dive. Nitrox offers divers longer BT at certain depths and can be very toxic at other depths. You should do some more homework on the basics of nitrox to find out whether it will be beneficial to YOU as a diver, not whether your LDS says you should, or could or need to use this gas. Try doing a search on the board for nitrox. There will be many discussions on this topic. Be careful about listening to your LDS as they MAY not know what they are talking about........I did say MAY NOT. I'm not trolling here, just stating a fact......as though none of us have ever had someone in a dive shop tell us something that was NOT TRUE! To answer your question in a very specific way......Do divers feel any different? Some say they feel better with the higher 02 content but that is NOT the reason you would use Nitrox of any blend. It has specific uses and restrictions. As I said, do some more homework to see if it has beneficial properties for you and your buddy/buddies or your type of diving. doole November 9th, 2003, 08:33 PM Been certified for years. I get it. No need for more homework. Just starting to wonder if that 'less fatigued' feeling after a nitrox dive was all in my head, after listening to the lds. Don't think so, but still wondering about the story. chrpai November 9th, 2003, 08:54 PM I assume "blind taste test" means that divers were diving profiles without knowing what was in their tank..... very intersting world..... that said, is it all in your head or is it science? Well I know what the official industry position is, but a friend of mine knows alot about diving phisiology ( we worked at Navy BUMED ) and his opinion is that its real. mwilding November 9th, 2003, 08:54 PM use of the phrase, "blind taste tests" pretty much tells you the veracity of the story... cornfed November 9th, 2003, 08:59 PM Blind taste test, ***? It ain't pepsi. What was your LDS trying to show? doole November 9th, 2003, 09:01 PM chrpai says... I assume "blind taste test" means that divers were diving profiles without knowing what was in their tank..... very intersting world..... that said, is it all in your head or is it science? Well I know what the official industry position is, but a friend of mine knows alot about diving phisiology ( we worked at Navy BUMED ) and his opinion is that its real. Mine too. Although conceivably they could have given air to a control group, ean to a test group and told everyone not to go below a particular depth. If so, you'd have to be interested in hearing the divers' qualitative reports. DandyDon November 9th, 2003, 09:13 PM About 2-1/2 years ago. Still have that issue, as it has a better Dive Operator Directory than those they've publsihed since. I hope we don't get into whether they are a worthy source to consider. They're interests are mixed, as are all paid publishers Anway, they did run tests with divers using tanks marked EANx, but half on air - above the soft bottom of 1.4. Their findings then included: (a) No one could tell (taste) the difference. So what? (b) Divers on Nitrox did feel less tired overall. I've never ntoiced it, and I usually dive it, but then - I'm old, fat, and out of shape. The big thing to me is that I get about 50% more bottom time at depth on Nitrox as compared to Air. Most of my dives are below 60 feet, and my average cost per dive on vacation is $200 a dive overall, so if I can safely get 50% more for my money, I am. My original instructor - whom I respected very much, and still do - did not teach it, and did not support it. Overhead and operating expenses were possibly a part of that, for a small town instructor. I got it elsewhere. don doole November 9th, 2003, 10:50 PM dandydon said... (a) No one could tell (taste) the difference. So what? (b) Divers on Nitrox did feel less tired overall. I've never ntoiced it, and I usually dive it, but then - I'm old, fat, and out of shape. The big thing to me is that I get about 50% more bottom time at depth on Nitrox as compared to Air. Most of my dives are below 60 feet, and my average cost per dive on vacation is $200 a dive overall, so if I can safely get 50% more for my money, I am.don Seems to me if they felt less tired, then there was a difference. In my own case, I can't say my bottom time is extended because I usually run low on gas or get too cold before I hit my NDL anyway. But I still like the stuff. I think it has to do with lung volume and CO2 retention, I just seem to feel better afterwards on EAN. Mo2vation November 9th, 2003, 11:49 PM chrpai once bubbled... I assume "blind taste test" means that divers were diving profiles without knowing what was in their tank..... very intersting world..... Yeah, sign me up for that test. Can you imagine signing the waver for that one? "here, breathe this... TRUST us..." I analyze all gas I breathe, Air or EAN. Scary. Back to the topic - I dive EAN. I've never "felt" a difference, as many of my friends do. However, many of these same folks recently 'tasted' bad air...and I didn't taste it. Maybe I'm a doofus, or maybe my senses aren't that sharp. I'm confident of this - I've never "felt" NOT being bent. I've never "felt" any differnece being close to bent or being far from bent. I've never "felt" fatugued after 3 days of diving air. And I've never "felt' mo bettah after 3 days of diving EAN. A lot of smart people tell me its good for me. I believe them. K
roakey November 10th, 2003, 06:03 AM doole once bubbled... Been trying to talk my lds into offering ean, and he said (yes - this is PURE hearsay) that in a "blind taste test" the divers were generally unable to identify whether or not they had been given nitrox, after a typical rec dive dive. Seeing that Nitrogen ongassing and offgassing is asymptomatic if you do it correctly, why the heck are they even considering "being able to identify Nitrox" as an argument in the first place? If nitrox is not important, I'd have whoever told you this compare 21% Nitrox against pure Nitrogen at depth, and see if he still doesn't think Nitrox or not matters... Roak roturner November 10th, 2003, 07:18 AM doole once bubbled... Been trying to talk my lds into offering ean, and he said (yes - this is PURE hearsay) that in a "blind taste test" the divers were generally unable to identify whether or not they had been given nitrox, after a typical rec dive dive. Anyone know if there's any truth to this? Some people say it makes a difference. I've never noticed but I never feel crappy after diving air either. I'd venture a guess that if you did an aggressive dive profile on air and then did exactaly the same profile on Nitrox that you could notice a difference because of the lower levels of residual nitrogen (asymptomatic bubbles or whatever). On the other hand I think if you dove profiles that left you with a comparable nitrogen load then I can't see hyow you would feel a difference..... Maybe you'd even feel worse on Nitrox because your dive would probably have been longer and in you could be more fatigued. R.. chrpai November 10th, 2003, 07:39 AM roakey once bubbled... Seeing that Nitrogen ongassing and offgassing is asymptomatic if you do it correctly, why the heck are they even considering "being able to identify Nitrox" as an argument in the first place? Roak Perhaps that is the key point to explain his opinion. He worked in a military diving environment where I suspect getting the job done took precedence over offgassing right. So he probably saw profiles where it sure as hell made a difference. 5615mike November 12th, 2003, 10:52 AM Mo2vation once bubbled... Yeah, sign me up for that test. Can you imagine signing the waver for that one? "here, breathe this... TRUST us..." I analyze all gas I breathe, Air or EAN. Scary. Back to the topic - I dive EAN. I've never "felt" a difference, as many of my friends do. However, many of these same folks recently 'tasted' bad air...and I didn't taste it. Maybe I'm a doofus, or maybe my senses aren't that sharp. I'm confident of this - I've never "felt" NOT being bent. I've never "felt" any differnece being close to bent or being far from bent. I've never "felt" fatugued after 3 days of diving air. And I've never "felt' mo bettah after 3 days of diving EAN. A lot of smart people tell me its good for me. I believe them. K I find it hard to believe that ANYONE would dive without knowing what was in their tank. Promoting such a test is grounds for arrest, or at least a good tounge lashing. jviehe November 12th, 2003, 11:14 AM 5615mike once bubbled... I find it hard to believe that ANYONE would dive without knowing what was in their tank. Promoting such a test is grounds for arrest, or at least a good tounge lashing. Oh, come off your high horse. Would you really ask the Coke people whether thats really Pepsi in the one, or could it be arsenic? I dive nitrox most of the time now, but I've been able to tell the difference in regards to fatigue vs air. cyklon_300 November 12th, 2003, 12:30 PM The decrease in fatigue using EAN becomes noticeable after MULTIPLE days of MULTIPLE dives... A single tank nitrox dive probably doesn't involve enough ongassing/offgassing to be produce detectable results in most individuals. doole November 12th, 2003, 01:15 PM Yes, it would make sense that it becomes more noticeable as the series of dives gets longer. BTW I like your moniker - my first adult reg was a Cyklon, so it keeps a special place in my heart. Not a smooth reg, though - kind of like driving a Shelby Cobra. Don Burke November 12th, 2003, 01:28 PM 5615mike once bubbled... I find it hard to believe that ANYONE would dive without knowing what was in their tank. Promoting such a test is grounds for arrest, or at least a good tounge lashing. I can think of a couple of ways to safely do the test double blind. I recall a test where the only first dive difference was a slight improvement in gas consumption on a shallow dive which involved swimming. I attribute that to regulator performance. My guess is that the improvement in fatigue on repetitive dives is due to the reduction in subclinical DCS. Damselfish November 12th, 2003, 02:19 PM jviehe once bubbled... I dive nitrox most of the time now, but I've been able to tell the difference in regards to fatigue vs air. And can you tell the percentage? :) Actually, if everyone in the test had the same profile enforced, one that was considered safe for any of the mixes involved, seems like you'd be pretty much set here. Aside from trusting someone else to make sure all tanks used in the experiment were within range. But if someone was actually attempting a real study, being careful about analysis, having it doublechecked, keeping precise records of everything, that would probably be ok too. There is some level of trust involved in all of this. Some people may check air tanks, but this is not common. If I'm diving air, I trust that someone hasn't accidentally filled it with Nitrox. doole November 12th, 2003, 02:29 PM Well I know I can. "Swiiish - aaaah! 32%. A good year, too."
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