Why Nitrox?

[DivetheRock]

Great. I'm very pleased with the opinions expressed so far. I think I understand what's good for me - I may do the Nitrox course soon as I have the money to spend right now, and I can take advantage of the "low introductory rate" of $99.
I think that having this certification will certainly broaden my understanding of diving and SCUBA in general (which wouldn't hurt), and would certainly be a plus if I find myself in a situation where I were wishing I had the certification under my belt (e.g. going on vacation with multiple dive day opportunities).
Thanks everybody for your help!

 

[HowardE]

My question is more "Why NOT nitrox"? I only pay $5 on average for a nitrox fill...

I just did a 45 minute total dive time yesterday with a max depth of 110 feet, and spend most of the dive at 95 feet, and still didn't go into deco. You can't do that on air.

I often hear of the "placebo" effect with "how you feel" after a dive. My question to people is "How do you measure (scientifically) how good you FEEL"? If you feel tired, can they measure that? If you feel revitalized, you feel it, how could it be measured?

Bottom line about nitrox is, there are SIGNIFICANT benefits of REAL NDL'S in depths between 50 and 130 feet. If I'm on a dive vacation, I would (and do) pay extra for nitrox as well (since I get cheap nitrox at home) - If I can extend safely my NDL's by 15-20 minutes on deeper dives... over a week long trip, I can get more than 3-5 hours MORE bottom time than people on air. Even on a single day trip, I can get as much as 30-45 more minutes bottom time than an air person can on a 1/2 day (2 tank) typical florida type charter boat.

 

[shakeybrainsurgeon]

My question is more "Why NOT nitrox"? I only pay $5 on average for a nitrox fill...

I just did a 45 minute total dive time yesterday with a max depth of 110 feet, and spend most of the dive at 95 feet, and still didn't go into deco. You can't do that on air.

I often hear of the "placebo" effect with "how you feel" after a dive. My question to people is "How do you measure (scientifically) how good you FEEL"? If you feel tired, can they measure that? If you feel revitalized, you feel it, how could it be measured?

Bottom line about nitrox is, there are SIGNIFICANT benefits of REAL NDL'S in depths between 50 and 130 feet. If I'm on a dive vacation, I would (and do) pay extra for nitrox as well (since I get cheap nitrox at home) - If I can extend safely my NDL's by 15-20 minutes on deeper dives... over a week long trip, I can get more than 3-5 hours MORE bottom time than people on air. Even on a single day trip, I can get as much as 30-45 more minutes bottom time than an air person can on a 1/2 day (2 tank) typical florida type charter boat.

There's nothing wrong with the placebo effect, you are right. In my practice, which is now primarily focused on pain management (another feeling that is dificult to quantify), I'll take a placebo effect, If the patient feels better, then it works... who cares why? That's why I don't agree with PADI questioning the benefit of nitrox for older divers...if it makes you feel better, use it.

As to the safety, I took the course last year and the position was that nitrox reduced the risk of DCS perhaps slightly, but also increased the risk of oxygen toxicity slightly. The problem is that DCS and O2 toxicity are so rare in rec diving that statistical analysis of the relative risks of air/EAN is not possible. It's just guesswork and speculation. The practical matter is we use it to extend bottom time and to reduce fatigue, not because it's safer per se.

 

[Darnold9999]

Don't use NITROX locally as I am almost always doing two dives or less and if two dives, rarely close together. I now always dive NITROX on a liveaboard if available. (Small sample so far, but am not likely to stop) 5 dives a day gives me significantly more bottom time and shorter SI's. I also feel much better diving Nitrox when diving that much. Have tried it on air and was wasted after three days. Five days - same conditions - on Nitrox and I am bouncing around the boat like I shaved 10 years off. SIGNIFICANT difference, and I really did not expect there to be any benefit so don't believe it is only in my head.

Don't bother locally as I don't really see there will be a benefit on a single tank or even on two unless the dives are spaced close together. In that situation I might dive Nitrox, but probably not as I would have to drain the tank and refill it.

Just my 2 cents.

 

[rjsimp]

I'm one of those divers that feels better post dive. I always feel better after a Nitrox dive as opposed to an air dive. If I dive less than 28% I'm dead tired. After Nitrox I can stay awake to enjoy the rest of the day.

My boyfriend says it is all in my head, but I totally disagree.

I agree with this as well.. I feel MUCH better after a Nitrox dive. On a recent trip to Cayman, I was diving Nitrox, but they were out of it many times so I had to switch between air and nitrox.. It was very noticable. Also since they were shore dives, I felt like I had more energy during the longer swims out to the reefs and back in since we would decend right away after entry..

This only makes sense, your body should have more energy and you should feel better breathing a higher % 02.. Talk to the Japanese and other places that have Oxygen Bars..

 

[shakeybrainsurgeon]

I agree with this as well.. I feel MUCH better after a Nitrox dive. On a recent trip to Cayman, I was diving Nitrox, but they were out of it many times so I had to switch between air and nitrox.. It was very noticable. Also since they were shore dives, I felt like I had more energy during the longer swims out to the reefs and back in since we would decend right away after entry..

This only makes sense, your body should have more energy and you should feel better breathing a higher % 02.. Talk to the Japanese and other places that have Oxygen Bars..

Human hemoglobin saturation is 99 + % on air, in other words, we have maxiumum oxygen loading of the blood on room air --- breathing enriched air is about reducing nitrogen, not increasing oxygen availability. Oxygen bars are, once again, placebos --- if they make you feel better, do it, but breathing extra oxygen does nothing for you unless you have intrinsic lung disease that lowers sats to less than 90 on air. The fatigue reduction of nitrox, if any, likely comes from less nitrogen residual.

 

[lamont]

Try a 2 fpm ascent from 30 fsw (15 mins going 30 feet) on 21% and you should feel better as well...

Nitrox just seems to have that 'built-in'.

 

[scubatexastony]

Human hemoglobin saturation is 99 + % on air, in other words, we have maxiumum oxygen loading of the blood on room air --- breathing enriched air is about reducing nitrogen, not increasing oxygen availability. Oxygen bars are, once again, placebos --- if they make you feel better, do it, but breathing extra oxygen does nothing for you unless you have intrinsic lung disease that lowers sats to less than 90 on air. The fatigue reduction of nitrox, if any, likely comes from less nitrogen residual.

kinda disputed your own reason for feeling better on enriched air....

More Oxygen = Less Nitrogen, Less Nitrogen = feel better.... at the surface, at depth, there's still less loading



tony

 

[rjsimp]

Human hemoglobin saturation is 99 + % on air, in other words, we have maxiumum oxygen loading of the blood on room air --- breathing enriched air is about reducing nitrogen, not increasing oxygen availability. Oxygen bars are, once again, placebos --- if they make you feel better, do it, but breathing extra oxygen does nothing for you unless you have intrinsic lung disease that lowers sats to less than 90 on air. The fatigue reduction of nitrox, if any, likely comes from less nitrogen residual.

Hmmm.. If you are fatigued or winded then isn't your body needing more oxygen? Anyhow, do the athletes that are fatigued getting a placibo effect when they suck oxygen after a hard run (watch football players )

I'm not a doctor, but there seems to be something to this. Either way as stated by somone else on this thread the placibo effect is worth something too and the reduced nitrogen residual should help you feel less fatigued after a day of diving.

 

[Kim]

Try a 2 fpm ascent from 30 fsw (15 mins going 30 feet) on 21% and you should feel better as well...

Nitrox just seems to have that 'built-in'.

This would seem to suggest that the speed and amount of Nitrogen offgassing is what makes you feel tired or not. Nitrox simply has less Nitrogen to start with so unless you've pushed it right to the NDL and your compartments are completely full anyway you probably started with less to lose. A very slow ascent allows Nitrogen to dissapate in a 'gentler' way. The quicker you 'force' Nitrogen out of your body would seem to make you increasingly tired up to the point of actual DCS.