gas obsorbsion

david_1 · 7th March 2008, 11:17

"it allows me to spike setpiont by just holding my breath for a few meters, so when i hit bottom i am ready and away with no messing about"

I read above on here. It raised a question in my mind my body needs o2 to work and I almost understand I need less as I dive deeper. but if I hold my breath I am starving my body of o2 ? ,when I start to breath again would my body just want more o2 so negate the holding breath part of the decent.

This is just a question :-) and I still dont dive rebreather....

David

jhaaja · 7th March 2008, 12:18

Your body will use more or less a constant amount of O2 per minute. That is roughly 1L/min, but goes higher at high workloads and lower while sleeping. Depth has nothing to do with it.

JH

Dutchy · 7th March 2008, 12:28

Quote: (Originally Posted by david_1)

"it allows me to spike setpiont by just holding my breath for a few meters, so when i hit bottom i am ready and away with no messing about"

No clue whatsoever was intended.

Quote: (Originally Posted by david_1)

"
I read above on here. It raised a question in my mind my body needs o2 to work and I almost understand I need less as I dive deeper.

No you don't. You need the same amound of molecules. At depth with a higher gas density you can:
- Breath a Nitrox that would be deadly on the surface. (e.g. with only 10% oxygen in it). At 40m it would still be as breathing 50% on the surface.
All this is speaking in absolutes. Relatively, when you compare it to OC the savings get higher with dept. A closed rebreather uses approx .7 liter oxygen per minute @ 100m whereas an OC diver at 90m uses 150 liter Trimix (@SAC=15l/min)

Quote: (Originally Posted by david_1)

"
but if I hold my breath I am starving my body of o2 ?

Your body has a large reserve. You can do some 5 minutes without breathing. It is the CO2 produced by your body that causes the breathing reflex.

Quote: (Originally Posted by david_1)

"when I start to breath again would my body just want more o2 so negate the holding breath part of the decent.

No not O2. It wants to get rid of the excess CO2. At the same time there isn't much to negate as rebreather divers don't need much gas in the first place.

Quote: (Originally Posted by david_1)

"
This is just a question :-) and I still dont dive rebreather....

I guess somebody did something for another reason than you may beleive. Maybe if you list the context things start to make sense. As for the not diving a rebreather. Good for you. All the money burning in your pocket and still many other options to consider....

David[/quote]

david_1 · 7th March 2008, 17:31

http://www.rebreatherworld.com/decom...ng-do-you.html

I was reading the above thread but did not want to hijack it.

Thanks for your replies it seems I still have more to learn :-) its cool being able to ask questions and getting real answers with any of the crap that can come from some other forums unless I ask a realy crap question...

I did sort know about ppo2 at depth but Dutchy answer was very well put..

David

***ScubaDadMiami*** · 7th March 2008, 17:48

We all had the same questions at one time or another. The purpose of this forum is to exchange information.

Dutchy · 7th March 2008, 18:30

Quote: (Originally Posted by david_1)

http://www.rebreatherworld.com/decom...ng-do-you.html

I was reading the above thread but did not want to hijack it.

Thanks for your replies it seems I still have more to learn :-) its cool being able to ask questions and getting real answers with any of the crap that can come from some other forums unless I ask a realy crap question...

I did sort know about ppo2 at depth but Dutchy answer was very well put..

David

I'm sorry I still don't know for sure what they meant.

On the positive side you're no longer alone in your not-knowing

jhaaja · 7th March 2008, 19:28

I guess he ment the fact that you can spike the loop ppO2 on descent if you just hold your breathe for a few meters so that the adv won´t add gas. Your setpoint will rise as ambient pressure is increasing and no diluent is diluting

JH

7th March 2008, 11:17	#1 (permalink)
david_1 New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jul 2006 Location: uk Posts: 28	gas obsorbsion "it allows me to spike setpiont by just holding my breath for a few meters, so when i hit bottom i am ready and away with no messing about" I read above on here. It raised a question in my mind my body needs o2 to work and I almost understand I need less as I dive deeper. but if I hold my breath I am starving my body of o2 ? ,when I start to breath again would my body just want more o2 so negate the holding breath part of the decent. This is just a question :-) and I still dont dive rebreather.... David
(Offline)

7th March 2008, 12:18	#2 (permalink)
jhaaja Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Mar 2005 Location: Finland Posts: 867	Re: gas obsorbsion Your body will use more or less a constant amount of O2 per minute. That is roughly 1L/min, but goes higher at high workloads and lower while sleeping. Depth has nothing to do with it. JH
(Offline)

7th March 2008, 12:28	#3 (permalink)
Dutchy SK#007 Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: Apr 2006 Location: Nieuwegein (The Netherlands) Posts: 699	Re: gas obsorbsion Quote: (Originally Posted by david_1) "it allows me to spike setpiont by just holding my breath for a few meters, so when i hit bottom i am ready and away with no messing about" No clue whatsoever was intended. Quote: (Originally Posted by david_1) " I read above on here. It raised a question in my mind my body needs o2 to work and I almost understand I need less as I dive deeper. No you don't. You need the same amound of molecules. At depth with a higher gas density you can: - Breath a Nitrox that would be deadly on the surface. (e.g. with only 10% oxygen in it). At 40m it would still be as breathing 50% on the surface. All this is speaking in absolutes. Relatively, when you compare it to OC the savings get higher with dept. A closed rebreather uses approx .7 liter oxygen per minute @ 100m whereas an OC diver at 90m uses 150 liter Trimix (@SAC=15l/min) Quote: (Originally Posted by david_1) " but if I hold my breath I am starving my body of o2 ? Your body has a large reserve. You can do some 5 minutes without breathing. It is the CO2 produced by your body that causes the breathing reflex. Quote: (Originally Posted by david_1) "when I start to breath again would my body just want more o2 so negate the holding breath part of the decent. No not O2. It wants to get rid of the excess CO2. At the same time there isn't much to negate as rebreather divers don't need much gas in the first place. Quote: (Originally Posted by david_1) " This is just a question :-) and I still dont dive rebreather.... I guess somebody did something for another reason than you may beleive. Maybe if you list the context things start to make sense. As for the not diving a rebreather. Good for you. All the money burning in your pocket and still many other options to consider.... David[/quote] __________________ = This post is environmentally friendly. It is composed of 100% recycled electrons only. = SK #007
(Offline)

7th March 2008, 17:31	#4 (permalink)
david_1 New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jul 2006 Location: uk Posts: 28	Re: gas obsorbsion http://www.rebreatherworld.com/decom...ng-do-you.html I was reading the above thread but did not want to hijack it. Thanks for your replies it seems I still have more to learn :-) its cool being able to ask questions and getting real answers with any of the crap that can come from some other forums unless I ask a realy crap question... I did sort know about ppo2 at depth but Dutchy answer was very well put.. David
(Offline)

7th March 2008, 17:48	#5 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 1,939	Re: gas obsorbsion We all had the same questions at one time or another. The purpose of this forum is to exchange information. __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
(Online)

7th March 2008, 18:30	#6 (permalink)
Dutchy SK#007 Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: Apr 2006 Location: Nieuwegein (The Netherlands) Posts: 699	Re: gas obsorbsion Quote: (Originally Posted by david_1) http://www.rebreatherworld.com/decom...ng-do-you.html I was reading the above thread but did not want to hijack it. Thanks for your replies it seems I still have more to learn :-) its cool being able to ask questions and getting real answers with any of the crap that can come from some other forums unless I ask a realy crap question... I did sort know about ppo2 at depth but Dutchy answer was very well put.. David I'm sorry I still don't know for sure what they meant. On the positive side you're no longer alone in your not-knowing __________________ = This post is environmentally friendly. It is composed of 100% recycled electrons only. = SK #007
(Offline)

7th March 2008, 19:28	#7 (permalink)
jhaaja Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Mar 2005 Location: Finland Posts: 867	Re: gas obsorbsion I guess he ment the fact that you can spike the loop ppO2 on descent if you just hold your breathe for a few meters so that the adv won´t add gas. Your setpoint will rise as ambient pressure is increasing and no diluent is diluting JH
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode