Nitrox and Fatigue: the Evidence

[Steelyeyes]

There is. It gives me longer NDLs.

Yep

 

[Storker]

There is. It gives me longer NDLs.

And lower N2 loading for similar bottom times.

Which, in itself, is A Good Thing (tm) no matter how you feel about it.

 

[RayfromTX]

We did a nice 160 minute dive on 32% today. We rode the computer at a 85 gf high. We were at 100 ffw for 20 minutes and then continued with 0 or 1 NDL as we climbed the slope up to 60 ffw where we spent another 40 minutes and then on up to 50 and then 30. We spent 60 at 20 and 10 just hanging out and floating along. By the time we surfaced our nitrogen loading was quite low. After cleaning up and having a bite to eat I fell asleep and took a 3-4 hour nap which is quite unlike me. These personal impressions we have of diving nitrox are pretty useless in understanding the benefits of nitrox. I could come away thinking that nitrox diving is exhausting and creates a feeling of fatigue, which would be nonsense.

What matters most to me is this. I get a longer bottom time within NDLs and the time I spend in the shallows is more effective in the shallows when breathing EAN. This is important because I have 4 tanks and gear to haul up the stairs and put in the car right after exiting the water and the less nitrogen in my tissues when I do that, the less is my risk of DCS.

I paid 35$ for my nitrox course, which is just the cost of the card if I recall correctly. I pump my own gas so the cost of nitrox compared to air is around $2.10 additional cost for each of us. We breathed 150 cu ft of gas of which 21 cu ft was the added O2 at 10 cents a cu ft. Each person's nitrox reality is different. I just wanted to add a data point which is at the opposite end of the scale from others expressed here as to cost.

 

[chillyinCanada]

Such a long nap! I am jealous

 

[Searcaigh]

For my personal local recreational preferences I dive 34% first then 40% for the second dive.

The majority of our diving is square profile with the deeper dives 26-30m then shallower second dives to 20--24m, but I still see people dive using air, which for me is pointless, who wants a 20 minute dive?

 

[tursiops]

We did a nice 160 minute dive on 32% today. We rode the computer at a 85 gf high. We were at 100 ffw for 20 minutes and then continued with 0 or 1 NDL as we climbed the slope up to 60 ffw where we spent another 40 minutes and then on up to 50 and then 30. We spent 60 at 20 and 10 just hanging out and floating along. By the time we surfaced our nitrogen loading was quite low. After cleaning up and having a bite to eat I fell asleep and took a 3-4 hour nap which is quite unlike me. These personal impressions we have of diving nitrox are pretty useless in understanding the benefits of nitrox. I could come away thinking that nitrox diving is exhausting and creates a feeling of fatigue, which would be nonsense.

What matters most to me is this. I get a longer bottom time within NDLs and the time I spend in the shallows is more effective in the shallows when breathing EAN. This is important because I have 4 tanks and gear to haul up the stairs and put in the car right after exiting the water and the less nitrogen in my tissues when I do that, the less is my risk of DCS.

I paid 35$ for my nitrox course, which is just the cost of the card if I recall correctly. I pump my own gas so the cost of nitrox compared to air is around $2.10 additional cost for each of us. We breathed 150 cu ft of gas of which 21 cu ft was the added O2 at 10 cents a cu ft. Each person's nitrox reality is different. I just wanted to add a data point which is at the opposite end of the scale from others expressed here as to cost.

You rode the NDL, of course you got no benefit from reduced nitrogen loading. You were loading nitrogen to the max.

 

[RayfromTX]

As has been said many times, benefits come in various forms. I benefited from a longer bottom time. Our visibility and temperatures are much better deeper so that is a substantial benefit. Later, I benefitted from improved off gassing in the shallows.

My tissues were barely in the yellow by the time I surfaced. It is misleading to say I was loading nitrogen to the max since this was an NDL dive at a gf of 85. I was a long way from loaded to the max. I did an hour at safety stop depths. Next time I do a dive like this I will check my surface gf of my leading tissue group. It will be quite low if my guess is correct.

I simply want to clarify these points for those that might take more meaning from what you wrote than you probably intended. These are issues that have and will always be repeatedly discussed ad nauseam. The biggest problem with coming to an understanding of these issues is that those that devote their lives to studying it only agree on the fact that they aren't able to definitively say how it works or where the lines are. People's physiology varies greatly for many reasons and testing these things has ethical limitations so we aren't getting answers in a form that makes official declarations clear and unequivocal.

 

[tursiops]

These personal impressions we have of diving nitrox are pretty useless in understanding the benefits of nitrox

Exactly. Too bad people keep posting them.

 

[Doc]

Exactly. Too bad people keep posting them.

You started it.

 

[dmaziuk]

Such a long nap! I am jealous

You know that natural non-prescription sleep-promoting candies are now legal in your entire country, yes?