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Nitrox: Narcosis myth?

Discussion in 'Advanced Scuba Discussions' started by northernone, Jun 18, 2017.

  1. Alexandros

    Alexandros Garibaldi

    # of Dives: 50 - 99
    Location: Athens
    2
    1
    3
    Hello,

    What I've been taught is that Nitrogen becomes narcotic at a certain partial pressure. So that by reducing the percentage of Nitrogen on the mixture we have less pp at the target depth, thus lower probability of narcosis.

    So, could someone explain with simple words (I cannot really interpret the papers linked in this thread) why a Eanx32 mix for a dive at 30m does not reduce the nitrogen narcosis effect?

    If nitrox has no relation with nitrogen narcosis, I'm also wondering why nitrogen narcosis is not observed in dives deeper than 40m with trimix, say 18/45 mix. Nitrogen is still present there, isn't it?

    Thanks in advance for any explanation.
     
  2. PfcAJ

    PfcAJ Orca

    # of Dives:
    Location: St Petersburg, Fl
    6,278
    3,956
    113
    Oxygen is likely narcotic and increased po2 affects co2 retention which is for sure narcotic.
     
    rongoodman likes this.
  3. northernone

    northernone Instructor, Scuba Staff Member

    # of Dives: 500 - 999
    Location: Waskaganish, Northern Canada
    1,210
    617
    113
    Co2, oxygen AND nitrogen are responsible for narcosis at depth. As you stated, reducing the partial pressures of these gasses (by going shallower or introducing helium into your breathing mix) will reduce the narcotic effect.
     
  4. KevinNM

    KevinNM DIR Practitioner

    2,062
    757
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    Gasses get denser with depth. Denser gasses increase work of breathing, which can cause CO2 issues too. Deep air is not a great idea for more than one reason.
     
    PfcAJ likes this.
  5. KWS

    KWS ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: SE TEXAS
    3,273
    613
    113
    I have like others taken pictures of stuff at the 130 range and when back on the boat many I don't remember taking and others I don't know why I took them. That lack of clarity is not there when I use nitrox. I am also less fatigued after using nitrox. another point that many say is not true. I can tell when it takes so much effort to climb a ladder to et back on board the boat. I suspect that there is little benefit for those that are joc's or have no lungt issues known or not. Those that do,,, seam to see the same benefits that I do. I cant begin tot comprehend the idea of nitrox does not reduce narcosis. the math is there for the nitrogen portion. less nitrogen less effect from nitrogen. I have no way to determine the effects from O2 but as clarity goes,,,,, to use notrox and have O2 be equal to N2,,,, is a personal non verifiable claim for me. I don't dive trimix often enough to use that as a comparison factor. I'm sure every gas has a narcosis factor to it. What I don't believe is that narcosis,,, for what ever gas,, happens at the same depths. In sure He is narcotic but not at any depths I would ever dive to.
     
  6. AJ

    AJ Solo Diver

    # of Dives: 200 - 499
    Location: Netherlands
    375
    146
    43
    There's no academic proof there is an positive effect from using higher percentage of O2. That does not mean it is not there, just there no academic prove either positive or negative, yet.

    What could be is that you're a 'CO2 retainer'. Which means your body is absorbing CO2 easy or is not efficient in releasing CO2. I know, because I'am on the same boat. I have a very very slow breathing rhythm while diving (very low gas usage). Higher O2 percentage probably helps me to reduce CO2 build up, and therefore I feel better after the dive. Nitrox works for me too. Scientifically proof or not, I don't care :wink:
     
  7. RayfromTX

    RayfromTX Student Of Gaseous Manipulation Staff Member

    # of Dives: 50 - 99
    Location: Hill Country of Central TX
    1,221
    670
    113
    I think there actually is some academic proof but it is not widely distributed yet, perhaps because of the need for further peer review. @Dr Simon Mitchell do I have this right?
     
  8. AJ

    AJ Solo Diver

    # of Dives: 200 - 499
    Location: Netherlands
    375
    146
    43
    Ah, that's interesting. I had this debate with many buddy's but was'nt aware of any proof for what I'am sensing.
     
  9. MaxBottomtime

    MaxBottomtime Solo Diver

    # of Dives: 1,000 - 2,499
    Location: Torrance, CA
    6,580
    4,117
    113
    I would run, not walk to the nearest neurologist if I were you. Not remembering taking photos when you get back on the boat is probably not because you were breathing air at 130 feet. There is no secret ingredient in nitrox that relieves fatigue nor narcosis, but if it feels good to you then go for it.
     
  10. tarponchik

    tarponchik Manta Ray

    # of Dives: 500 - 999
    Location: USA
    927
    96
    28
    Nitrox is oversold but on a different premise: that divers get less fatigued diving on Nitrox. I've read this multiple times on Scubaboard and heard again on a boat recently.
     

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