Larger gas capacity and increased DCS risk?

[knowone]

Everything is correct theoretically but the correct answer comes from doctor Superlyte27 and doctor awareness and The essentials of deeper sport diving LIPPMAN is far more user friendly.

 

[ianr33]

I asked a question a while back about N2 absorption and working hard on a dive.
http://www.scubaboard.com/forums/ad...20898-does-exertion-affect-n2-absorption.html

This is my understanding of the situation:

Breathing fast (ON ITS OWN) will not result in an increase in N2 uptake and hence DCS risk.A nervous new diver probably comes into this category.

Working hard on a dive increases perfusion,so more N2 is absorbed and DCS risk increases.

If you are breathing fast due to working hard (e.g. swimming into a current) then,yes,you will absorb more nitrogen and should do longer safety/deco stops.

 

[tmassey]

I asked a question a while back about N2 absorption and working hard on a dive.
http://www.scubaboard.com/forums/ad...20898-does-exertion-affect-n2-absorption.html

This is my understanding of the situation:

Breathing fast (ON ITS OWN) will not result in an increase in N2 uptake and hence DCS risk.A nervous new diver probably comes into this category.

Working hard on a dive increases perfusion,so more N2 is absorbed and DCS risk increases.

If you are breathing fast due to working hard (e.g. swimming into a current) then,yes,you will absorb more nitrogen and should do longer safety/deco stops.

This is the answer I was looking for: clear and definitive. Now I just need the factual basis for these statements! . I haven't yet read the material that's been linked to above, but I will soon.

Thank you all for your help and information. Any additional resources to consider would be appreciated as well. This conversation has been most helpful.

 

[ianr33]

This is the paper I mentioned in my last post. It changed my way of thinking.
http://archive.rubicon-foundation.org/dspace/bitstream/123456789/2981/1/6535313.pdf

 

[boulderjohn]

Maybe I'm having a "stupid attack" but I don't have even the beginning of a clue what that means.

Here's an experiment you may wish to try.

Click on the poster's name, and you will get a menu of choices. One of them is to read other posts by the poster. Read through them for a while and see if you detect a pattern.

 

[Mike Boswell]

I asked a question a while back about N2 absorption and working hard on a dive.
http://www.scubaboard.com/forums/ad...20898-does-exertion-affect-n2-absorption.html

This is my understanding of the situation:

Breathing fast (ON ITS OWN) will not result in an increase in N2 uptake and hence DCS risk.A nervous new diver probably comes into this category.

Working hard on a dive increases perfusion,so more N2 is absorbed and DCS risk increases.

If you are breathing fast due to working hard (e.g. swimming into a current) then,yes,you will absorb more nitrogen and should do longer safety/deco stops.

From TS&M's Post #29 on the thread you cite:

Quote:

This is and is not true. Gas in the alveoli exchanges across the capillary membranes according to driving gradients. The process does take time, but not much. When fresh gas reaches the alveolus, the gradient is maximal; as that gas takes up CO2 and nitrogen, the process slows. As the gas is refreshed with inspired volume, the partial pressures of offgassed substances falls, and diffusion becomes more rapid again. So, if you run more gas through the alveolus, the net effect is that the gradient driving offgassing INCREASES, as the blood is trying to equilibrate with a lower partial pressure in the alveolus. This is why true hyperventilation drives your CO2 down.

Similarly, when you are at depth, increasing your ventilation rate is going to keep the partial pressure of nitrogen HIGHER in the alveolus, and may result in a small amount of additional uptake.

Whether the increased uptake (and the increased muscle perfusion) compared with the shorter time at depth for the same gas volume results in a net increase or decrease of total gas absorption would be an interesting question. But for those of us whose dives are limited by preset times or NDLs or cold, rather than gas, it would certainly be possible to execute two dives with exactly the same time/depth profile, but possibly with quite different nitrogen uptakes.

Unquote.

 

[flots am]

Here's an experiment you may wish to try.

Click on the poster's name, and you will get a menu of choices. One of them is to read other posts by the poster. Read through them for a while and see if you detect a pattern.

Care to elaborate?

flots.

Edit: Nevermind. I thought you meant my posts. Quite a few of knowone's posts are incomprehensible.

 

[Mike Boswell]

Care to elaborate?

flots.

Edit: Nevermind. I thought you meant my posts. Quite a few of knowone's posts are incomprehensible.

Careful, flots ... That's what people said about Einstein.

 

[Mike Boswell]

I asked a question a while back about N2 absorption and working hard on a dive.
http://www.scubaboard.com/forums/ad...20898-does-exertion-affect-n2-absorption.html

This is my understanding of the situation:

Breathing fast (ON ITS OWN) will not result in an increase in N2 uptake and hence DCS risk.A nervous new diver probably comes into this category.

Working hard on a dive increases perfusion,so more N2 is absorbed and DCS risk increases.

If you are breathing fast due to working hard (e.g. swimming into a current) then,yes,you will absorb more nitrogen and should do longer safety/deco stops.

I am not sure that you can separate the two so easily. Work and stress elevate breathing, but by the same token, rapid breathing elevates stress. This is a fundamental principle behind Yoga and meditation techniques.

IMO, if a calm person starts to breathe faster, he will induce a higher level of physical activity in the body, which in turn will increase N2 uptake and DCS risk.

 

[knowone]

The timbre of that drum you are beating is sounding somewhat flat.
The skin must be flaccid.
I am beginning to wonder what you are balancing in that boulderjohn.

Impartiality as a ScubaBoard Board Guide I think not.

Cheers Emile.