How much easier is Nitrox 32% / EAN32% on your body?

How much easier or better does 32% feel for you in terms of post-dive tiredness?

  • Nitrox makes me more tired.

    Votes: 0 0.0%
  • Nitrox is about the same as Air.

    Votes: 27 51.9%
  • 1.5 Nitrox dives feels like 1 Air dive.

    Votes: 3 5.8%
  • 2 Nitrox dives feels like 1 Air dive.

    Votes: 9 17.3%
  • 3 Nitrox dives feels like 1 Air dive.

    Votes: 3 5.8%
  • The above selection approximately scales-up linearly for me (3:2, 4:2)

    Votes: 2 3.8%
  • The marginal benefit (w.r.t. tiredness) of Nitrox decreases with further dives.

    Votes: 2 3.8%
  • Its perceived positive effect fades and eliminates with more diving experience.

    Votes: 10 19.2%

  • Total voters
    52

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

For all I know, I might be less tired, if I dove it like air.
 
I dive Nitrox with about the same profile as I did with air. When I was diving air, after a couple of days (4 or 5 dives) I had to take a "day of rest". On Nitrox I dive 12 or 13 days straight and feel great. It may be a myth. I don't care. As long as I can afford Nitrox, I will be using it. I just feel better. :)

Cheers -
 
Exactly 4% better.
 
I dive Nitrox with about the same profile as I did with air. When I was diving air, after a couple of days (4 or 5 dives) I had to take a "day of rest". On Nitrox I dive 12 or 13 days straight and feel great. It may be a myth. I don't care. As long as I can afford Nitrox, I will be using it. I just feel better. :)

Cheers -

I tended to think and express the same view, then I ran a few tanks of hyper air. I felt just as good after those dives as I did on Nitrox.

That brings up the question to me of...”do people that feel better when diving Nitrox feel better because they’re diving Nitrox...or because they’re breathing gas that is of a higher quality/filtered more (the air that the oxygen was blended with) vs. regular breathing gas/air?”
 
So at this stage roughly 1 in 3 feel a benefit of nitrox. And that feel it, it's seems to be a decent feeling.

I posted this poll with the assumption that it was a given nitrox was beneficial. In my limited diving experience I hadn't (yet) come across anyone saying otherwise, and I assumed the dive shops weren't just after a few nitrox $ either as it's often 'recommended'.

I wonder, as being part of the minority group, the next time I dive nitrox, given now I know its effect is not clear cut or at least for the majority of divers there is no effect, will my feeling be the same or is my placebo bubble about to be popped.

The votes can be altered. It'll be interesting to see if Nitroxers shift camps.
The biggest advantage to diving EAN, at least for rec diving, is that it's ultimately a safer gas due to reduced nitrogen onloading. Whether it makes on "feel better" or not, it's easier on your body than diving air. The question of whether or not it makes you feel better, in my opinion at least, also has to take into consideration the cost of diving EAN. For me, diving Cozumel this last weekend and only doing 5 dives, the monetary cost of $14/cylinder outweighed the benefit of diving EAN. My SAC rate doesn't get me anywhere close to NDL on air so diving EAN doesn't really help much in that respect. The only thing I can say though is that if diving EAN indeed would've helped with the painfully massive headache I got Friday, then it's possible the cost would've been less of an issue, especially seeing as how I spent $35 on two bottles (or $25 for one) of 800mg Ibuprofen at one of the local pharmacies.
 
The biggest advantage to diving EAN, at least for rec diving, is that it's ultimately a safer gas due to reduced nitrogen onloading. Whether it makes on "feel better" or not, it's easier on your body than diving air.
Although this is said a lot -- "Nitrox is safer than air" -- the statement misses some important points, in addition to the reduced safety benefit of now having a Maximum Operating Depth to keep track of.

An example will clarify: the PADI tables for air give you 55 mins at 60 ft (NDL, pressure group W), and 35 mins to get to group N. Remember that the pressure group expresses how much residual nitrogen is in your body. The table for 32% gives you 90 mins at 60 ft (NDL, group X), and 48 mins to get to group N; the 32% gives you 84 mins to get to group W.
This means: if you dive to the NDL on Nitrox you are actually taking on MORE nitrogen (group X) than you would diving to the NDL on air (group W). If you dive to group N on air you get 35 mins, whereas to group N on Nitrox you get 45 mins, but you are in group N either way, so you have the same nitrogen uptake. If you dive 35 mins on air you are in group N, but 35 mins on Nitrox is group J, so less residual nitrogen. The air NDL (group W) is 55 mins, but diving for 55 mins on Nitrox is just group P. That region from 55 mins on Nitrox (group P) to 84 mins on Nitrox (group W) is the sweet spot for Nitrox versus air; you can exceed your air limits with Nitrox and have less residual nitrogen anywhere in that sweet spot....with the most reduction in residual nitrogen occurring for small exceedance of the air limit, and least if you go toward the Nitrox limit.

You can find your sweet spot on the tables for any depth by looking at the NDL for air, and then finding the Nitrox pressure group with the same number. Example: at 80 ft the air NDL is 30 mins, group R. On 32%, group R is 41 mins. So you can have up to 11 mins more bottom time on Nitrox and still not have more residual nitrogen than you would ahve with air.....but if you go to 41 mins, you have lost any benefits of using the Nitrox in terms of nitrogen uptake. In fact, the Nitrox NDL is 45 mins (group T), so you can do worse than air if you dive the Nitrox to its NDL.

Conclusions:
  • Diving either gas to the same pressure group gives the same residual nitrogen.
  • Diving Nitrox using air tables DOES give you reduced nitrogen uptake.
  • Diving air or Nitrox to their respective NDL gives you MORE nitrogen uptake on Nitrox.
  • If you are using Nitrox to exceed the air bottom times, there is an exceedance amount that is in the sweet spot, i.e. you get more bottom time but you still get less residual nitrogen. Example: depth 100 ft, air NDL is 20 mins (group O), but Nitrox for 20 mins is just group K. You can spend longer than 20 mins with Nitrox, and your pressure group keeps increasing, until you get to 26 mins for group O, even though the NDL for Nitrox at 100 ft is 30 mins. the time between 30 mins and 26 mins is your don't-go-there zone, or else you are doing worse on Nitrox than you would have with air. This means: if using Nitrox, stay about 20% under your NDL in order to control your nitrogen pressure group.
Caveats:
  • This is from the PADI/DSAT tables.
  • Nobody dives square profiles like the tables.
  • Use your computer, but don't go near the NDL, especially on Nitrox.
 
Seems like odd poll choices. In general I'll say that I'm not tired after a dive on nitrox while i am tired after a dive on air. It's not like nitrox give me "extra" energy, I just am not worn out and needing a nap. That's from memory though, because as soon as I figured it out I switched to nitrox full time. It's been about 4 years since I've done a dive on regular air. Given that it generally costs somewhere between $2-$5 extra per tank for nitrox, air just doesn't make any sense to me. Most dive days end up costing me over $100 (food, gas, boat ride, fills). The cost is completely insignificant and there is a nice benefit.

Placebo effect? Maybe I guess. Placebo effect is a real thing though, so I personally do not care if that's what it is.
 
the statement misses some important points, in addition to the reduced safety benefit of now having a Maximum Operating Depth to keep track of.
Well, if someone - like me - anyhow has a personal depth limit somewhere around 30m due to narcosis, that is a very minor issue.

I don't enjoy going deeper than 30-ish meters (100-ish feet) because I thoroughly dislike being stupid when I'm in an environment which may well kill me on a bad day. With EAN32, I'm still at around 1.3 bar pPO2, so not much risk of toxing.
 
That region from 55 mins on Nitrox (group P) to 84 mins on Nitrox (group W) is the sweet spot for Nitrox versus air; you can exceed your air limits with Nitrox and have less residual nitrogen anywhere in that sweet spot....

Nitrox is another tool. Generally not being gas limited, ^^^THIS^^^ is why I dive nitrox especially in Coz. The profiles I dive there are made for nitrox. Yes, I could dive differently and dive air, but the dives/profiles are one of the reasons I enjoy diving there. Not having my computer "screaming" halfway through my second dive is something well worth the added cost ($10/tank at my shop) as well as the longer BTs. I understand others dive differently there and don't feel the extra cost is warranted...dive and let dive :). For me personally, it's an easy choice. Same goes for liveaboards with 4/5 dives per day for multiple days. For other locales it depends on the circumstances. As far as feeling better, I haven't noticed a difference beyond the added diving enjoyment. All IMHO, YMMV.
 
SportDiver had an Ask DAN article on July 10, 2019 about this topic

Ask DAN: Can Diving with Nitrox Prevent Fatigue?

"While the reports of this phenomenon are widespread and often fiercely defended, our best understanding is that nitrox can prevent fatigue about as well as a manatee can pass for a mermaid: There might appear to be some similarity on a foggy day, but a close look reveals little resemblance to the truth."
Read the rest of that article. The issue is not nearly as clear as even what you quote. They are using just one older study ti buttress their opinion, and ignoring mire recent research that does nit support their opinion. This is usually called cherry-picking.
 
https://www.shearwater.com/products/swift/

Back
Top Bottom