Yup, and if you want more education in that can of worms, do a search for "red blood cell rigidity" esp. on the more technical boards.lamont:
CO2 retention question
- Thread starter wetvet
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Matthew
Contributor
lamont:
what does 1-1-1 mean? thanks.
wb416
Contributor
Matthew:
Rather than a 3 minute at 15'... a one minute stop at 30', 20', 10' is advised (I think this is the DIR forum) on NDL dives (as a minimum).
hope that helps....
bob
Matthew
Contributor
wb416:
I see. Thanks.
Wetvet,
As posted, your neckseal, is more a culprit than breathing air, but air is not helping. Simple things like a 'one notch too tight' neck seal will create a chain of events regarding the lack of O2/blood supply to your head, thereby triggering the body to increasing CO2 to force you to breathe harder. The vicious cycle just gets worse and worse even if you do absolutely nothing and just breathe and hover simply because of that ill fitting seal.
So, with that build-up generated as a by-product being produced faster than it's being metabolized, you're looking for ways to minimize it (in fact, your body needs a little CO2 in the system). It's also 120x more narcotic than N2. Narcotic potency is measured as inverse proportion to the square root of the molecular weight of the gas. Yes, it may be 5x heavier, but the effect is 120x more potent. Metabolism helps, but just recognize that somewhere between 5x-120x is the truth and that just plain sucks!
What do I do??
-Trim the seal and get a good fit that doesn't restrict blood flow to the head. OK, can't do that underwater.
-Slow down and move slowly. Reduce your effort.
-Breathe deeply and deliberately. Shallow breathing is common with CO2 buildup.
-Reduce N2. Add more O2 or He. RBC rigidity from N2 was already mentioned. Plus, N2 is heavy to breathe especially with a tight neck seal. Yes, O2 is narcotic as well, but it's also metabolized and the key ingredient that you're trying to get to your head! Unfortunately, there's no oxygen window benefit with Nitrox less than EAN50 at the recreational depths that your talking about. Plus, you don't want to open that window when you're working. However, EAN32 still gives you advantages over EAN36 or EAN40 (again no real O2 benefit) by giving you 1) the depth flexibility and 2) the benefit of added NDL time. Of course, the best choice is 30/30 for your dive. He is so much easier to breathe and its benefits already mentioned. Real benefits of He are physiologically noticeable with contents of 30% and greater. You've basically reduced your N2 content by half when compared with air. It is also the gas of choice for extended exposure (beyond NDL) at recreational depths.
You can conduct some simple tests: dive air, Nitrox 32, and 30/30 (of course after you get proper training) and swim at 90ft for 100 yards, complete the dive and record how you feel immediately after the dive, 1 hour, 2 - 3 hours, and then 4 -6 hours. Even with a tight seal, I don't think you'll run into problems with He. I've tried to work hard to increase CO2 at 100' with 30/30 to see if I could get that 'out of gas' feeling. Couldn't do it. Or trust those that have tried it, and start feeling good from now on out!
DIR is about taking every advantage possible before, during, and after the dive, and gas selection is one of many considerations...Do I dare say your equipment is another?
Hope that helps.
Sincerely,
H2
As posted, your neckseal, is more a culprit than breathing air, but air is not helping. Simple things like a 'one notch too tight' neck seal will create a chain of events regarding the lack of O2/blood supply to your head, thereby triggering the body to increasing CO2 to force you to breathe harder. The vicious cycle just gets worse and worse even if you do absolutely nothing and just breathe and hover simply because of that ill fitting seal.
So, with that build-up generated as a by-product being produced faster than it's being metabolized, you're looking for ways to minimize it (in fact, your body needs a little CO2 in the system). It's also 120x more narcotic than N2. Narcotic potency is measured as inverse proportion to the square root of the molecular weight of the gas. Yes, it may be 5x heavier, but the effect is 120x more potent. Metabolism helps, but just recognize that somewhere between 5x-120x is the truth and that just plain sucks!
What do I do??
-Trim the seal and get a good fit that doesn't restrict blood flow to the head. OK, can't do that underwater.
-Slow down and move slowly. Reduce your effort.
-Breathe deeply and deliberately. Shallow breathing is common with CO2 buildup.
-Reduce N2. Add more O2 or He. RBC rigidity from N2 was already mentioned. Plus, N2 is heavy to breathe especially with a tight neck seal. Yes, O2 is narcotic as well, but it's also metabolized and the key ingredient that you're trying to get to your head! Unfortunately, there's no oxygen window benefit with Nitrox less than EAN50 at the recreational depths that your talking about. Plus, you don't want to open that window when you're working. However, EAN32 still gives you advantages over EAN36 or EAN40 (again no real O2 benefit) by giving you 1) the depth flexibility and 2) the benefit of added NDL time. Of course, the best choice is 30/30 for your dive. He is so much easier to breathe and its benefits already mentioned. Real benefits of He are physiologically noticeable with contents of 30% and greater. You've basically reduced your N2 content by half when compared with air. It is also the gas of choice for extended exposure (beyond NDL) at recreational depths.
You can conduct some simple tests: dive air, Nitrox 32, and 30/30 (of course after you get proper training) and swim at 90ft for 100 yards, complete the dive and record how you feel immediately after the dive, 1 hour, 2 - 3 hours, and then 4 -6 hours. Even with a tight seal, I don't think you'll run into problems with He. I've tried to work hard to increase CO2 at 100' with 30/30 to see if I could get that 'out of gas' feeling. Couldn't do it. Or trust those that have tried it, and start feeling good from now on out!
DIR is about taking every advantage possible before, during, and after the dive, and gas selection is one of many considerations...Do I dare say your equipment is another?
Hope that helps.
Sincerely,
H2
coralcuts
Guest
Hey Harry, what about long predive surfsce swims? sans scooter. I agree with everything else you wrote though. Let me know if you come back down as I need more practice sessions prior to the next taxing class. Or I can come up there I guess.
sans scooter. I agree with everything else you wrote though. Let me know if you come back down as I need more practice sessions prior to the next taxing class. Or I can come up there I guess.
Susan, if your back can handle it, we have a large group at Marineland tomorrow morning. Some are planning to dive all day.
coralcuts
Guest
Phil, thanks for the offer but I have to be at the pool teaching tomorrow. otherwise I would be there. Plus I have a steel 95 to return to you one of these days.MaxBottomtime:
coralcuts:Hey Harry, what about long predive surfsce swims?
Susan,
I paid the price for those long surface swims later that day when I crashed in the car several hours later and couldn't get up for the Angel's game. Easily attributable to CO2 in the body throughout the dive and use of air. You guys need scooters down there from a safety standpoint(reduction in CO2, reduction in gas consumption, fighting surf, and massive increase in fun factor) and some surface support to reduce all the physical exertion, not to mention keeping the grill hot and chow ready! :10:
It would be more fruitful to come up here: mix, tanks/stages, scooters, bottle work with a high concentration of T1/T2/T3/C1/C2 trained team members/mentors. Easy access to great diving with and without boat. Training is also pretty rigorous based on team member expectations and environment (low vis and currents).
Rally all them sunloving fruit and nuts Nor/SoCal DIR divers and make a road trip up here for some great great stuff that we have from 10-300+' Again, we have easy access to all the technology here at a fraction of the hassle and physical exertion!
Sincerely,
H2
coralcuts
Guest
Hey Harry, having originally trained in the great lakes, I am aquainted with lo vis and variable conditions. Granted I would love a dive sherpa and will audition any who volunteer, the fact remains that what doesn't kill me makes me stronger. So if beach diving in doubles and stages is all I can get, I'll do it. As long as maciek doesn't fry us topside. I'll just keep the O2 tanks away from him. But I am seriously considering a trip up there but need to wait for new seals on the old drysuit. I'l let you know. Maciek are you with me? Jon? Gina?
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