PERCEPTIONS vs FACT ????

[Walter]

I know the "experts" say that there is no evidence for the effect, but personally, I feel noticeably less tired after repetitive dives if I'm using Nitrox.

I don't believe any expert has said there's no evidence. I'm aware of one double blind study that has been conducted on the subject. The evidence from that study suggests that the reason people feel less tired after diving with nitrox is the placebo effect. The botton line is if you feel better, you feel better. It does not matter if you feel better because of some inherent quality of a higher % of oxygen or because your mind tells you to feel better. Either way, you feel better.

 

[HateCheese]

I haven't noticed a difference. If there is any post-dive fatigue benefit, it would appear slight enough that it isn't noticed at least by me.

 

[DeputyDan]

Yes I feel better with Nitrox.

I have no doubts on the subject!

 

[Thalassamania]

I don't believe any expert has said there's no evidence. I'm aware of one double blind study that has been conducted on the subject. The evidence from that study suggests that the reason people feel less tired after diving with nitrox is the placebo effect. The botton line is if you feel better, you feel better. It does not matter if you feel better because of some inherent quality of a higher % of oxygen or because your mind tells you to feel better. Either way, you feel better.

Title: Measurement of fatigue following 18 msw dry chamber dives breathing air or enriched air nitrox. Authors: Harris, RJ; Doolette, DJ; Wilkinson, DC; Williams, DJ

Issue Date: 2003

Publisher: Undersea and Hyperbaric Medical Society, Inc.

Citation: Undersea Hyperb Med. 2003 Winter;30(4):285-91.

Abstract: Many divers report less fatigue following diving breathing oxygen rich N2-O2 mixtures compared with breathing air. In this double blinded, randomized controlled study 11 divers breathed either air or Enriched Air Nitrox 36% (oxygen 36%, nitrogen 64%) during an 18 msw (281 kPa(a)) dry chamber dive for a bottom time of 40 minutes. Two periods of exercise were performed during the dive. Divers were assessed before and after each dive using the Multidimensional Fatigue Inventory-20, a visual analogue scale, Digit Span Tests, Stroop Tests, and Divers Health Survey (DHS). Diving to 18m produced no measurable difference in fatigue, attention levels, ability to concentrate or DHS scores, following dives using either breathing gas.

Description: Undersea & Hyperbaric Medicine : Journal of the Undersea and Hyperbaric Medical Society, Inc.

URI: Rubicon Research Repository: Item 123456789/3975

Appears in Collections:Undersea and Hyperbaric Medicine Journal

That's the classic work, the problem is that it only addresses fatigue on a single 18m dry dive.

 

[lil' castaway]

I feel better when I'm diving on nitrox. I don't feel as tired, even after a two-tank dive. If it's all just in my mind - I don't really care.

 

[Walter]

MaryAnn, I feel better when you're my buddy. If it's all just in my mind - I don't really care.

 

[under water]

Title: Measurement of fatigue following 18 msw dry chamber dives breathing air or enriched air nitrox. Authors: Harris, RJ; Doolette, DJ; Wilkinson, DC; Williams, DJ
bla blah blah..
That's the classic work, the problem is that it only addresses fatigue on a single 18m dry dive.

How much fun can a dry dive be??
Seems to me it would be hard to justify that test as anything close to how I and maybe the rest of us use EAN.

 

[lil' castaway]

MaryAnn, I feel better when you're my buddy. If it's all just in my mind - I don't really care.

Well I'm all for making you feel better my friend. Let's go diving!!!!

/Hugs\
MaryAnn

 

[adurso]

I started using nitrox due to the possibility of microbubble formation in areas of old injuries and surgical sites. Due to the reduced vascularity of these sites Ernie Campbell (ScubaDoc) suggested higher O2 mixes on air tables. Reduced fatigue was not an anticipated by product. I do, however, experience reduced fatigue.

 

[lamont]

Honestly, I haven't done a dive on air in so long, I'm no longer sure. But I'm quite convinced that, when I switched, I was sure it reduced my fatigue. But I also changed my ascent procedures at the same time.

I did have a personal experience that convinced me, beyond any argument (or facts), that subclinical DCS is manifested by fatigue. I did too many ascent drills in one night dive, some of them rather poorly controlled, and at 7 pm I was driving home like I was sedated. Stopping at a light, I'd nod off before it changed. The only time in my life I have ever felt like that was during residency, when I'd be up 48 or more hours.

I don't do multiple ascents in a training dive any more.

I had a similar experience on 21%, but there wasn't anything wrong with the profile. Switched to 32% and haven't had a recurrance, even on dives that are more aggressive in terms of gas loading and deco. Helium is actually even better, I usually don't even feel 'crunchy' after a 30/30 dive, much less sedated...

IMO, gas loading is nowhere near the entire picture...

Also, in addition to "driving home sedated", there's fever-like symptoms and chills that I've gotten before. This is probably 1-2% of dives, so I don't know if the previously mentioned study is doing enough dives to produce enough symptoms to get a statistically significant difference. It would also be useful to split up the subjects into those with PFOs and those without.