Reasons NOT to use Enriched Air?

[InTheDrink]

I'm convinced that reduced fatigue and no headaches are not due to any magical properties of nitrox but rather to decompression stress using air.

Slow down the ascents,extend the safety stops and the fatigue will go away.

Hmmm, I ascend fairly slowly and do a deep as well as shallow stop but I'll try even slower. I did notice that on shallower dives in the UK on air I am not getting headaches so perhaps there is something in it. Altho I have also stopped smoking immediately before a dive since diving in the UK so perhaps that helps too. As always, too many variables to make definite statements.

J

 

[String]

I did notice that on shallower dives in the UK on air I am not getting headaches so perhaps there is something in it. Altho I have also stopped smoking immediately before a dive since diving in the UK so perhaps that helps too. As always, too many variables to make definite statements.

J

Both of that screams CO2 retention which is by far the most common cause of diving headaches. Shallow dives, breathing resistance of the reg is less, partial pressures are less so no headaches. Smoking is also a great way to retain CO and indirectly CO2 and both these under pressure can cause that.

 

[HowardE]

Because you are not allowing any safety margin.

Please elaborate.

The FORUMLA for Best mix is (with 1.4 ppo₂ as the Target):

FO₂ = 1.4 (Target PPO₂) / ({Depth/33}+1)

or

Best Mix % = (whatever Target PP you want) / (ATA at Depth you're going to)

 

[Rick Inman]

The 1.4 / 1.6 is already a built in safety margin.

As to feeling better after nitrox... Sub-clinical DCS, that feeling of fatigue after a dive, I have read, can be due to the body acting on the increased nitrogen in the blood / tissues in a way that is similar to it fighting off the flu. Thus flu like fatigue, which is lessened by less N2 in the body.

I also feel better after doing deco on 100% verses 50% or 80%.

If this is all hogwash, please don't tell me and spoil the nice placebo effect I have working for me.

 

[DwayneJ]

The 1.4 / 1.6 is already a built in safety margin.

As to feeling better after nitrox... Sub-clinical DCS, that feeling of fatigue after a dive, I have read, can be due to the body acting on the increased nitrogen in the blood / tissues in a way that is similar to it fighting off the flu. Thus flu like fatigue, which is lessened by less N2 in the body.

I also feel better after doing deco on 100% verses 50% or 80%.

If this is all hogwash, please don't tell me and spoil the nice placebo effect I have working for me.

Check out the rebreather forums and discussions on modifying PPO2 levels based on depth and length of dive - There are good examples of individuals suffering oxygen toxicity between PPO2 1.4 and 1.6. The initial symptoms present themselves as involuntary spasms in their arms and legs and the individuals have recognized what was happening and moved to a shallower depth/lowered their PPO2 levels. I'm not aware of basic Nitrox training that recommends diving beyond 1.4 and certainly not beyond 1.6 PPO2.

 

[ianr33]

. I'm not aware of any training that recommends diving beyond 1.4 and certainly not beyond 1.6 PPO2.

Err.......pretty much the entire world uses 1.6 for deco.

 

[DwayneJ]

Err.......pretty much the entire world uses 1.6 for deco.

Task loading? Depth etc? Look at the original thread and the discussion on planning your total dive to PPO2 1.6 and max depth. Seems we have moved well past basic scuba discussions - Do you also believe novices should dive to 130 ft on EAN36 or routinely plan their dive using 1.6 PPO2?

 

[Blackwood]

Hmmmmmm, sounds like I have to put a lot more dollars in to get to learn the good stuff.

Check out the 5thd-X (erm... no URD) Intro to Tech video.

It was made by one of the only people on record as having rescued a toxing diver, and that's one of the topics covered.

 

[ianr33]

Do you also believe novices should dive to 130 ft on EAN36 or routinely plan their dive using 1.6 PPO2?

No,of course not.

You said:
" I'm not aware of any training that recommends diving beyond 1.4 and certainly not beyond 1.6 PPO2."

Well, stage deco training uses and recommends 1.6. for decompression. I agree this is nothing to do with basic scuba but you said ANY which is a strong word.

 

[dumpsterDiver]

To me nitrox is more dangerous if you have the potential to drop too deep for the mix at the particular dive site you are at.

Another disadvantage for nitrox divers that use partial pressure mixing..if you are ever so carelsss as to forget to check your mix, AND forget to check your pressure gage on descent...it IS possible to find yourself at 60 or 80 feet and 500 lbs of pure oxygen in your tank. It is just super, super important that nitrox divers make sure they are going down with a full tank.

when diving less than 40 feet or more than 140 I will use air. For pretty much everything in between it is nitrox.