Static PB's

[efattah]

Personally I think the passive exhale dive gets its main benefit from reduced narcosis & DCS risk, as well as reduced effort during the descent.

I think it is deceptive to say that it reduces the chance of shallow water blackout -- true, but only because it makes deep water blackout more likely.

During an inhale dive, blackout typically occurs in the last 15m -- where the safety freediver is waiting. During an exhale dive, there is no reason to believe the blackout will occur at the end -- it could occur at 30 or 40m if the diver overstepped his limits -- and for most divers, diving with one or two safety freedivers only, there isn't anyone down at 40m to drag them back up.

However, the risk of blacking out at the absolute bottom (60m+) is minimized, due to decreased O2 toxicity & decreased CO2 narcosis... although the extreme negative pressure might cause a blackout...


Eric Fattah
BC, Canada

 

[TMcKee]

Well, couldn't you take the lesser of two evils and do a full lung dive but exhale quickly in the last 15m to 30m? I don't know...Im just asking. Would this work? I've always seen that pic of kirk exhaling on his way up...

Just wondering..

 

[JimGlynn]

Sebastien-
Great to have your input. I really like your monofin style. Do you have any videos on the web? I remember seeing a dynamic video last yr. but I cannot find it anymore.
Jim

 

[Sebastien]

True Eric: reduced narcosis, O2 tox and DCI are important (I think I may have alluded to that previously elsewhere).

When you are referring to a deep black-out due to extreme negative pressure are you referring to extreme vasoconstriction and concommitant increase in arterial CO2 partial gas pressure? If so, my stand on that is that arterial CO2 uptake is reduced because circulation is reduced to central organs. In addition I feel there might be a significant depression of central organ metabolism, e.g., bradycardia, reduced brain temp. Furthermore, the high increase in haematocrit (splenic emptying) and reduced N2 reduces the negative effects of CO2 in the blood through the 'haemoglobin diluting effect'.

The danger I think lies in in the intense vasoconstriction and associated shift to anaerobiosis in prime movers --> plenty of oxygen to maintain consciousness but none to propel the body back-up. On the other hand, there may be a hidden mechanism which modulates muscle oxygen supply so as to strike the best possible balance in energy conservation. In other words, the aerobic limit varies according to effort not just vasoconstriction and hence depth.

Ofcourse a hypoxic episode could occur during descent but unlikely due to the increase in ppO2, despite low lung volumes.
As the dive progresses and the blood shift increases pulmonary shunting increases, i.e., pulmonary bypass through the Thebesian circulation such that gas exchange is impeded. If gas exchange is very much reduced this would create a significant difference between alveolar and arterial ppO2 such that O2 is stored, becoming re-available during the re-expansion (ascent) phase.


Bottom line: speculation and conjecture.
Best knowledge is first-hand experience.


PS: Jim, try www.amphibios.info


Available next thursday
Sebastien
Townsville, Aust.

 

[ivan]

hi Seb

Wow are you in the Cairns pool every Thursday if so for how much longer. Like I said im from Wonga beach so im about 100km north of you but If I can find some time I will definetly give you a ring. It would be so cool to meet someone who knows what you mean when you say freediving, yep Ive never met anyone who freedives without a gun.

BTW way I dont think I could do your training im not a good diver, but I would like to watch you train maybe if thats alright. Maybe I will get to see a monofin in real life. I work usually from 8 or 9 pm till 12pm but maybe I will get a couple of days off work.

cheers

 

[ivan]

hi Seb

Ive been thinking hard and planning a way to get there. I think I can maybe get there this thursday if your there. The only problem is I dont own my own car so I might have to be VERY NICE to my parents so they should lend me there car. How long are you training for. I will Pm you also cos people may get angry if I keep asking you questions.

cheers

 

[A Brownsword]

Wow, this discussion is certainly pushing the envelope on my knowledge of physiology! I'm particularly interested by this statement, however:

Originally posted by Sebastien
The real reason for exhales is to reduce the energy cost of the descent by using gravity as the propulsive force, since the energy cost of passive drag vs. active drag is about 1/3. The benefit outweighs the corresponding energy cost in ascending, through loss of buoyancy. Free-fall distance varies in direct proportion to my anticipated dive depth. I vary free-fall distance by varying the lung volume and not by adding ballast. I believe the use of ballast to counteract positive buoyancy could be a fundamental flaw in current freediving methodology.

Obviously this is what aquatic mammals do as well since we're the only ones silly enough to carry around lead weights. May I ask what depth you weight yourself to be neutral at then? And do you vary it at all, when changing your diving suit or switching from fresh to salt water, for example?

One nice thing about weights is that you (or your buddy) can drop them with the advent of a problem. On an exhale dive you have no ability to improve your bouancy.


On the subject of exhalation during the last part of the ascent (as the photo of Kirk shows, and I believe he recommends in his courses), this obviously relieves the problem of chest pressure due to expansion... but what effect does it have on the O2/CO2 partial pressures? Is such an exhalation during the last 10m or so going to convince your body that it has to breathe more or less urgently?

Thanks for the great discussion.

 

[TMcKee]

Originally posted by ivan
hi TMckee

I have never thought of what you just said and it kinda makes sense. Are you saying that in the first 33ft of the dive that this is when I will be using most of my precious 4L of air. SO once you start getting past 33ft you shouldnt have to waste so much air equlising. Can you tell me a little more about this please.

Zipy yeah 100ft is more like it

cheers

Typically the biggest pressure change is between 0 - 33fsw. I found that in a decompression chamber or diving deeper usually didn't require much clearing. Correct though, after 30fsw or so, you shouldn't have to equalize quite so often.

 

[cdavis]

Hi all, fabulous discussion

Just to add an historical example, pearl diving was a big thing in polynesia before WWII, no fins, crude masks, down with a big rock, not sure how they got up. Several reporters at the time, some eyewitnesses, report dive times of 3-4 minutes, depths of up to 45m, commonly 36m. What is really interesting is the description of the divers going down with only half a full breath and begining to exhale on the bottom, half way through the dive, and continuing to exhale until they surface. Any comments from the experts? Has anybody tried anything like this?

 

[Sebastien]

Reply to: A Brownsword

May I ask what depth you weight yourself to be neutral at then? And do you vary it at all, when changing your diving suit or switching from fresh to salt water, for example?

One nice thing about weights is that you (or your buddy) can drop them with the advent of a problem. On an exhale dive you have no ability to improve your bouancy.

On the subject of exhalation during the last part of the ascent (as the photo of Kirk shows, and I believe he recommends in his courses), this obviously relieves the problem of chest pressure due to expansion... but what effect does it have on the O2/CO2 partial pressures? Is such an exhalation during the last 10m or so going to convince your body that it has to breathe more or less urgently?

That will vary with the type of dive I do; I have no fixed recipe.
That being said, I'm approx. 1.5kg -ve at the surface at FRC (wet) without a wetsuit in seawater. I'm fortunate enough to be diving at present in 29 degree Celcius in the ocean at the moment so wearing a wetsuits isn't an issue presently.

I've never dived in freshwater and so have no opinion on that.

For me this issue of neutral buoyancy is irrelevant. I only seek to reduce effort at the surface by being positive whilst breathing and negative whilst diving. One of my aims is to minimize buoyancy changes. I cannot increase +ve buoyancy greatly whilst ascending but that's ok as I'm prepared to work anaerobically if I have to.

Kirk may be be purposefully exhaling on ascending if his aim is to improve venous return during the final few metres. Buccal pumping could prevent adequate venous return and result in loss of consciousness.


Reply to Ivan of Wonga Beach:

It doesn't matter if you can't do my training, sometimes I can't do it too....intent and attitude is much more important I think.
Try me on 47 240 019 (Townsville) if you can't get me in Cairns.



Sebastien Murat
Townsville, Aust.

 

[MANTA99]

I made a new PB dry static of 5min last night beating my old PB by 45 seconds, I still don't think I got any contractions, thats a good thing though I sp'ose. Very happy.

 

[alastair]

TMcKee asked an interesting question that nobody replied to. If I understood correctly he asked :

Can I make a full lung dive (to reduce deep BO) and then, as I near -15m on the way back up exhale to reduce the vacuum effect of expanding lungs (in order to reduce the chance of SWB).

In addition, I wondered if sprinting the last 15 to the surface in 'anaerobic mode' would help or hurt the situation.

Al

 

[Walrus]

New Dry Static PB = 6.32

I've never been keen on doing dry statics, but lately since I'm doing CO2 tables dry anyway.....

Did a 3.50 CO2 table, rest = 2 min, static, 1 min, S , 30 secs, S, 20secs, last static. Then did 2 minutes hyperventilating, and did a 6.32 static. That's a PB for me but doesn't really count the same as doing it in the water. Still it's encouraging and shows that I'm capable of more so just have to try harder in the pool :duh

I've never pratcised dry statics and still they are easier then wet statics? I suspect most people would be better at dry statics then wet.

P.S. Also managed a 3 min full exhale static (no reverse packing) doing the same short rest straight after doing a table.

Cheers,
Wal

 

[Bill]

table?

Aloha Wal
I'm curious about the workup. Is it something you were taught or what works best or..? It's about as far from my workout today as you can get. Is it meant more for spearfishing? Congrats on the PB.
Bill

 

[Walrus]

Hi Bill,

I've just been doing CO2 tables dry because I can't get down to the pool everyday. I just thought I'd try a couple of statics after since I was warmed up anyways. Thought I read a post where you did a static straight after tables ? The short rest and hyperventilating was something Eric had done on some of his routines, so gave it a try. I don't know if it would make a reliable routine, ie one that would work in a comp.

The CO2 table seems like a shortened down version of the ones on the UK freediver website. Fixed static, then the rests are 2min, 1min, 30sec, 15sec. (The last one is sometimes hard to keep the rest so small) Got it from Sacha Dench who was on the UK team a few years back, then kicked arse on our team last year

My static routine in water is fairly normal, although I do 3 warmups. Something like 3.30, 4.30, 5.00, 6 min rest, max. (PB is 6.08)

Cheers,
Wal

 

[ivan]

hi

Congrats Wal i knew you could always beat your wet static times on dry there sooooo much easier eh. Did you see on tv last week the 7:30 report there was a topic on freediving it had sacha and Antony judge his dad etc talking about and doing freediving. Ive been away for about 3 weeks been working with 2 jobs 14hours a day so no freediving for me anymore

cheers

 

[zipy]

hi

first to manta99 and Walrus cong. on new PB (manta99 I haven't noticed your post till now)

To alstar:
it makes no sence to me how could you reduce the vaccum efect by exhailing (but that is just me)

I wondered if sprinting the last 15 to the surface in 'anaerobic mode' would help or hurt the situation

As i know in 'anaerobic mode' your muscles do not take O2 from blood (at that time you brn ATP) so in theory it would help.
And by sprinting for last meters you are faster up

And to Ivan :
Welcome back!

Zipy

 

[ivan]

hi Zipy

How it goin, Im pretty sorry man cos I havent really been able to practice statics anymore to give you a run for your money, been working to much. But maybe on my days off I will give a try at it.

Have you done any pbs lately ?

cheers

 

[alastair]

it makes no sence to me how could you reduce the vaccum efect by exhailing (but that is just me)

Yeah Zipy, it's probably stupid, but I suppose that exhaling when you have a small lung volume would reduce the rapid expansion of your lungs as you enter the last part of the dive.

You'd be 'throwing away' whatever O2 you've got left in your lungs, but presumably that isn't much...

Al

 

[Walrus]

5.01 1st Static ! (Wet, No warmup)
Not a Max PB but certainly a PB for a 1st static. Very suprising, my wet static PB is only 6.08.....

Training with Brad (Loopy) at the pool yesterday, and really didn't feel like doing statics, so I thought I'd just do one for the hell of it. I normally do a bit less then 4 minutes on a first static, thought if I felt good I'd try and beat Brad's final static (4.31). Had a moderate breathe up, normal breathing then about 10 fast & deep breaths. Contractions started at about 2.20 but were very mild. Got to 4.30 and was still quite comfortable, so kept going, aproaching 5 minutes contractions still weren't that fast. Popped up after 5 feeling good, like I could have done quite a bit more.

Contractions started quite early but didn't seem to speed up as much as it normally does on a Max static. It felt more like when you get contractions early on when they are slow and mild, but then extended for a longer duration......
Yeh really wierd didn't think I could do that, then again it may just be a fluke. I'll have to try it again.

Cheers,
Wal