To Nitrox or not to nitrox ,Why and how ?

[D_B]

I too do not want my gages to tell me something that is not, whether it's the time of day or my NDL

I want the most accurate info I can have, then I will decide what cushion I want to add to my NDL based on ... the conditions , the dive, and how I feel that day

 

[BoltSnap]

I don't believe that one should set their dive computer to anything but the REAL gas mix they are breathing. It is not only the NDL they have to keep up with, but also all other variables one has to keep track of when breathing EAN. As it was mentioned above, one should see the real NDL limits in their dive computer based on the real gas they are breathing but they would leave a "healthy" safety margin in their Dive Time to get the "physiological" advantage of using EAN.

 

[ade_eccles]

Re: fatigue - lots of divers (myself included) feel less tired after a dive on nitrox - can it all really be due to a placebo effect? Is there a chance that some of the fatigue could be to do with nitrogen loading and therefore breathing nitrox would reduce this (same as per a shallow dive, which I don't feel tired after) ? A lot of posts have indicated that there is no evidence for nitrox reducing fatigue but does anyone have any links to these studies ?

 

[Rhone Man]

I don't believe that one should set their dive computer to anything but the REAL gas mix they are breathing.

Unless you are using a Suunto. Then I add 1% or so to the actual EAN to dial it back to reality. It is still more conservative than my other computer, but at least it is closer...

 

[D_B]

sugar pills do work though

Less nitrogen loading ... but maybe that goes with the many posts I've seen here on SB that said they feel less tired after dives when they changed how they come up - slowed their accent rates, more stops, etc... better outgassing

 

[ade_eccles]

sugar pills are awesome !!

yep, slower ascents would make sense also re: nitrogen loading

one other thought - diving deeper seems to put the body under greater stress & breathing nitrox reduces the Equivalent Air Depth.

Therefore, it seems to me that it should reduce that stress on the body - should this not also potentially translate into a reduction of fatigue post dive ?

 

[blue steal]

I too do not want my gages to tell me something that is not, whether it's the time of day or my NDL

I want the most accurate info I can have I

This has been an interesting thread, thanks for all the information.
I have a question, slightly off topic, but am curious.
In COZ, I do two dives, first dive to a max of 90' for a BT of 60-65' (multilevel), then a SI of roughly 1:00.
Second dive at a max. of 60-70' for BT of 60-65'.
I find myself with plenty of air, but out of time (at NDL) always on the second dive.
So, would it help to extend BT to dive the first dive with air (.21), and use Nitrox, (either .32 or .36) on the second dive?
Or just use Nitrox on both dives?
Thanks, now back to topic.
I don't notice any difference in Nitrox versus Air in terms of feeling tired or fatigued.

 

[diverrex]

I don't believe that one should set their dive computer to anything but the REAL gas mix they are breathing. It is not only the NDL they have to keep up with, but also all other variables one has to keep track of when breathing EAN. As it was mentioned above, one should see the real NDL limits in their dive computer based on the real gas they are breathing but they would leave a "healthy" safety margin in their Dive Time to get the "physiological" advantage of using EAN.

I can understand that rationale but for myself I don't use it as a hard and fast rule but vary it by circumstance. When we go to Bonaire we use nitrox because it's free. Our typical dive day and dive profiles are 3 dives daily each around 60-65 fsw max and lasting 60-70 minutes. We always have surface intervals over an hour and usually several hours between dives 2 and 3. With that schedule and profiles our air NDL never comes within 20 minutes of deco. And PPO and oxygen exposure also doesn't come into play. Under those conditions I don't switch my computer to Nitrox settings. I am well within the limits of air, well within the limits of Nitrox, but since Nitrox is free I use it as one more safety measure.

I am one who also does not feel any fatigue difference on air or nitrox. I wish I did feel less tired after nitrox diving but don't. That applies to diving where I am well above air limits as stated above or when using nitrox settings and pushing near the limit of NDL.

 

[doctormike]

This has been an interesting thread, thanks for all the information.
I have a question, slightly off topic, but am curious.
In COZ, I do two dives, first dive to a max of 90' for a BT of 60-65' (multilevel), then a SI of roughly 1:00.
Second dive at a max. of 60-70' for BT of 60-65'.
I find myself with plenty of air, but out of time (at NDL) always on the second dive.
So, would it help to extend BT to dive the first dive with air (.21), and use Nitrox, (either .32 or .36) on the second dive?
Or just use Nitrox on both dives?
Thanks, now back to topic.
I don't notice any difference in Nitrox versus Air in terms of feeling tired or fatigued.

Well, I'm not going to bother doing those calculations since assuming a square profile, you would have blown way past your NDL on air (25 minutes at 90 feet) on the first dive.

I'm assuming that you aren't doing a square profile (as you said multilevel), which means that you can't do any calculations based only on the maximum depth. That's what dive computers do, they calculate NDLs with non-square profiles so you get credit for time spent at shallower depths.

Not sure why you would only use Nitrox on the second dive, unless you wanted the ability to drop below the MOD at some point on the first dive.

And, to summarize this thread in one sentence: Nitrox lets you extend your NDL, which is useful if that is the limiting factor in the length of your dives, and if you won't be going below the maximum operating depth of that particular mix.

 

[EastTNDiver]

Re: fatigue - lots of divers (myself included) feel less tired after a dive on nitrox - can it all really be due to a placebo effect? Is there a chance that some of the fatigue could be to do with nitrogen loading and therefore breathing nitrox would reduce this (same as per a shallow dive, which I don't feel tired after) ? A lot of posts have indicated that there is no evidence for nitrox reducing fatigue but does anyone have any links to these studies ?

I only have anecdotal musings to back up my opinion, but I don't believe it's placebo...at least, not for everyone. I remember my first nitrox dives. I had gone to the quarry to meet up with a bud, and we had a full day of diving...just like we had done many times in the past. While we did analzye our mix on site, and made the appropriate adjustments to our computers, the thought of nitrox quickly faded from our forethoughts, as we were heavily into practicing tech oriented skills that day. After getting home, I proceeded to do a few things around the house, when my wife commented on how perky I was and asked if we had not gotten in as much diving as usual (as I was usually kinda sluggish after such a full day of diving). Initially, I just shrugged off her comments, but then a light bulb went off for me..."Ah-hah! This was my first nitrox dives!" Like I said...purely anecdotal...but, I do believe it helps me with fatigue.