exhalation on the ascend?

[jero]

exhalation on the ascent?

This is a question directed mainly (but not excusively) for those of you who has been on the Kirk's classes.
I saw a picture of Kirk Krack ascending and exhaling before the surface. I have learned (I am a Mediterannian - old-school - bi-fin - yoga kind of freediver ) not to exhale before the surface cause the air is much more valid inside then on the outside.
Is this exhaling before surface another Kirk's trick or what?
Can someone please explain why does he do that?

 

[Chefkoch]

Many freedivers hold their breath until they reach the surface, so after reaching it, they have to exhale. This can cause blackout.
When you exhale underwater, you can inhale immediately after reaching the surface. I have learned to inhale first, especially after a difficult dive.

 

[jero]

I also inhale first but I don't exhale while my lungs are still under pressure. Actualy, I first reach the surface, INHALE as much as I can and then exhale.

 

[Jon]

If you exhale in the last 10 feet the idea is that you will be less likely to succumb to shallow water black out do to the vacume effect. That is, 02 in your blood stream gets sucked back into your lungs as they reexpand during the last 10 feet of ascent.
This is how he explained it in his clinic. I now do it on all of my freedives. I have no idea if it makes a difference because I have never blacked-out.
Jon

 

[jero]

I was hoping for that kind of response!
I just didn't understand - 02 in your blood stream gets sucked back into your lungs when you don't exhale before surface or when you do?
My guess is the first thing but I have to make sure. It does make sence - exhaling you actually keep your lungs from expanding to much, am I right?

 

[Jon]

Terry Mass does a better job of explaining it in his book FREEDIVE. He talks about the decent when the air in your lungs gets compressed and forces 02 into the blood stream. On the way back up your lungs start to reexpand. That means they suck 02 back into the lungs FROM the bloodstream. If you exhale during the last 10 feet, the area of the greatest difference in pressure, you may help eliviate the lung vacume effect.
I hope I explained it OK. The book is an excellent resource. I strongly recommend buying it.
Jon

 

[efattah]

Exhaling on ascent

Exhaling during the final part of the ascent is one of the most debated techniques in freediving. It is true that a 'reverse flux' of O2 from the blood to the lungs has been measured to begin around -8m, but if or when this happens is HIGHLY dependent on many things. For example, if you pack your lungs before you dive, you will start with a greater volume; this means your lungs will expand more during the ascent, and the reverse flux will be greater. But, if your O2 consumption rate is high enough, the situation becomes even more complicated. I have done some more research in this area and the bottom line is that it is very complicated. So, the question remains--should you exhale on the ascent, and if so, how deep, and how much? The answer is: under certain specific conditions, it MIGHT be helpful. In my case, I usually exhale at about 1m from the surface, which doesn't prevent reverse flux, but it allows me to inhale right after surfacing. I know Brett would exhale deeper, starting around 5m. I do know that if you exhale too much, too deep, your epiglottis can slam shut and you won't be able to inhale for several seconds upon surfacing. Because of that, always 'err' on the side of exhaling later, and less, or not at all. The way I see it, it really would only help if you were near blacking out, which you normally shouldn't be--but if you try exhaling when not near blacking out, you could start too deep, or exhale too much by accident, causing yourself new problems. So I don't recommend exhaling during recreational dives, except at maybe 1m from the surface.


Eric

 

[Kirk Krack]

People get confused when they hear you exhale upon ascent and conjure up idea's that you start deep at around 10m when in fact it's very shallow and as Eric Fattah metioned, he to occassionally exhales upon ascent even though it's only 1m below the surface.

My exhalation during ascent is usually around the 2m depth with a max 3m and isn't a full or forced exhalation, but a relaxed exhalation bringing lung volume to around tidal volume which is the volume of air in your lungs you usually breath at.

Another reason we start a slow exhalation upon ascent (2m average) besides reducing the 'vacuum effect' and helping take in immediate breaths instead of exhaling which can cause dramatic CO2 drops and then vasoconstriction is packing. Packing (carpa in french) puts pressure on the heart and reduces or disrupts venous blood flow and thereby cerebral arterial blood flow which is why people will feel light headed if they pack to much.

During the last part of your ascent especially if you've packed you'll start to feel the expansion of the air. Try packing and head to 10m, then slowly pull up the line and discover where you feel the lungs expand beyond a normal deep inhalation. Probably starts around 3m quite noticably.

Some people can get around 20% more volume on top of their normal lung volume with packing. By the time you've reached between 2-3m on a full pack, your lungs are back to a normal full volume. Above that the continued expansion can put pressure on the heart and again prohibit venous blood return and eventually cerebral blood flow because of the interuption.

Keep in mind that most people taught skin diving and almost ALL spearfisherman do this when they practice snorkel displacement clearing. Forceful exhalations at the surface can cause different atrial and ventricular arrhythmias as noticed by Dr Conneau in the European Journal of Applied Physiology and Occupational Physiology.

Not sure about the epiglottis slamming shut, I've never experienced it or anyone I've worked with, but I imagine if you exhaled fully and forcefully you could cause this to happen. Again that's why it should be done relaxed and not forced.

In the end, most of us probably exhale during ascent even though it's only 1 or 2 meters below the surface and not 10m like most people think when they first hear about it.

Sincerely,

Kirk Krack
Vancouver, Canada

 

[Stephan Whelan]

Images

Cliff has given me a couple of images from Kirk's performance freediving clinic...showing how to exhale.

Kirk first:

 

[Stephan Whelan]

Brett

And now Brett LeMaster...

 

[jero]

What about the people that don't pack before dive?
Is it better to hold the air untill the surface?

 

[Kirk Krack]

Jero,

Please keep in mind that there is much speculation as to why it might be beneficial or not. My opinion is only my opinion and it's based on what we believe and what has worked for Mandy Cruickshank, Brett LeMaster and Martin Stepanek in their world records.

I always exhale in the last 2m (more or less) regardless of whether it's a dive with packing or not, a target dive or a fun dive. I believe that upon surfacing it's most important to get the gas in your lungs immediately and utilize that properly. In the clinics we call the type of breathign we practice upon return to the surface "hook breathing". Whether it's the proper name for the description of the breathing is irrelevant, most importantly it's utilizing the air you've just taken in properly.

I believe the first 15 seconds are the most important as to whether you'll suffer from a hypoxic episode because whatever air you take in, needs time to move from the alveoli, to the capillaries through the pulmonary circulatory system to the heart, then pump from there to your brain. I think it was suggested that it takes 20 beats of the heart to complete a full circulation?

Within CAFA competitions the competitor must be able to look at the judges in the eye, signal OK and remove thier mask/goggles/nose clip, etc. It's my experience that most noticable problems will happen within that 15 seconds and if they can make it past that, then chances are they'll continue to be fine.

One of the area's in your body that read your CO2 levels is the chemoreceptors in the aortic branch of the heart along with the cartoid artery. This is the area where arterial blood is being distributed to the head and the rest of the body. This area reads CO2 levels very quickly after inhalation/exhalation due to it's proximity to the heart.

It's suggested that by exhaling your allowing a short adaptation time to the decrease in CO2 and that the shift of CO2 won't be as dramatic thereby causing an extreme vasodialation because of the CO2 levels being read by these chemoreceptors.

This is what Dr. Andrew Blaber at Simon Fraser University has suggested the reason why it might prove beneficial. Again this is only an opinion and hasn't been studied, although it is something they want to in the future.

Keep in mind that a short time is very short and that if you start exhaling at 3-2m your only exhaling for around 2-3 seconds or shorter.

I exhale in the last couple of meters to the surface whether I pack or not. Some do and some don't. Till the facts of a scientific study come back, we'll continue to each do our own meathods. I'm always looking to improve and if it's suggested that we should hold till the surface, I can change :>)

Sincerely,

 

[tuboludo]

All my live I exhaled on assent, but a few years ago a free diving instructor told me that I should not exhaled underwater since it would increase my chances of getting a blackout!

I always felt comfortable exhaling underwater and it always gave me a little extra oxygen when I mostly needed it, but the last three years I haven’t been doing it because this instructor at a free diving school told me not to do it???!!!

So now I am really, really confused, because you guys are basically telling me that I should exhale on my way up which I always found natural!

So should I go back to my old ways and not fear the shallow water black out?

 

[Simos]

All my live I exhaled on assent, but a few years ago a free diving instructor told me that I should not exhaled underwater since it would increase my chances of getting a blackout!

I always felt comfortable exhaling underwater and it always gave me a little extra oxygen when I mostly needed it, but the last three years I haven’t been doing it because this instructor at a free diving school told me not to do it???!!!

So now I am really, really confused, because you guys are basically telling me that I should exhale on my way up which I always found natural!

So should I go back to my old ways and not fear the shallow water black out?

You should get a buddy :inlove

 

[tuboludo]

You should get a buddy :inlove

Oh, even weirdoes like me have buddies, but none of them free dives, let alone, go for a swim in the hot summer breeze, so imagine asking them to go diving in cold waters with low visibility? No, I am all alone out there which is all okay since I am used to it, but seriously, exhaling or not exhaling on ascending??? (on this question you dudes are my buddies!)

 

[Mullins]

I'd like to play Russian roulette. Which handgun can people recommend? I'd like one with a nice ergonomic handle, because I'm worried about wrist injuries.

If you're diving hard enough for exhaling at vs. below the surface to make any difference at all to your safety, you're diving hard enough to make solo diving very, very dangerous. There are at least a couple of people in recent memory who signed up to freediving / spearfishing forums, said "I dive alone but it's ok, I don't push it hard" then blacked out and died.

It's, ahh, also worth noting that the post you responded to was written 11 years ago

 

[trux]

I always felt comfortable exhaling underwater and it always gave me a little extra oxygen when I mostly needed it,

Tuboludo, could you explain how you get extra oxygen by exhaling?

 

[tuboludo]

Tuboludo, could you explain how you get extra oxygen by exhaling?

Well, here is the thing. The last couple of years I have not been exhaling on ascent since I was told by a free driving instructor that if I did so I would have a greater chance of experiencing shallow water black out. But before I was told this I always had the habit of exhaling on my way back up to the surface, something I have done since I was a kid and I have never experienced any black outs doing so! (haven’t experienced any black outs ever for that matter).

I have been in a few diving situations where I were under water for too long and was desperate for air – one time when I was only 14 years old (or 13, I don’t remember the exact age for this incident) I almost drowned because my leg got caught in an anchor rope at the depth of 12 meters. Both then in that very desperate situation and in other not so desperate situations, I have experienced that exhaling when I really feel in need for some fresh air, gives me a little bit of extra oxygen (or at least that is how it feels like) so the urge to get to the surface and breath fresh air is postponed for a moment. And when I was younger I kind of used this experience like “back-up” when I was diving, knowing that I could prolong my dive by using this technique.

I don’t know how else to explain this…. Maybe some small reserve of unused oxygen gets pushed out into the blood stream when I empty my lungs for air?! I am no medical expert. But like I said, I have only used this technique as a last resort when I was desperate for air and of course the extra relief only last for short moment, but I am pretty sure that this “short moment” saved my life when I was 14 and I was pulling myself up the anchor rope with the anchor hanging on my leg, because I in the dark mud at the bottom of the lake had wrapped my leg into the anchor rope and I couldn’t see anything and I didn't have a knife with me to cut the rope.... have never dived without a knife since that incident :inlove

So when I read in this post that I should exhale on ascent I just got kind of confused, because I used to do that, but stopped doing it because a “professional” told me that it is dangerous… what is your opinion on this matter?

 

[trux]

Tuboludo, I'd advise to have a read of some basic principles of freediving theory and of freediving physiology. It is important to understand that the urge to breathe and hypoxia have very little relation. So when you feel an immense panic and a very stronge urge to breathe, you very often and in fact most likely are very far from being hypoxic. And in contrary you can have no urge to breathe at all, being deeply hypoxic and blackout without going through any panic state or rush for escape. As long as you do not understand these principles, and do not know how they are triggered, you cannot dive safely. Your exhaling certainly did not save your life at all, did not inject any miraculous O2 into your veins, and it is certainly no backup reserve. The only what it can achieve is suppressing the urge to breathe, which again is dangerous because it can lead to even quicker hypoxia.

Exhaling as a trigger of stronger DR can be _perhaps_ used in case the DR did not really kicked yet in, but it is a highly speculative manoeuvre, and will not work for everyone, and in all situations. The question is whether the reduced O2 consumption through stronger DR outweights the loss of PaO2, so I would really advise avoiding to rely on it as a backup measure.

 

[tuboludo]

Tuboludo, I'd advise to have a read of some basic principles of freediving theory and of freediving physiology. It is important to understand that the urge to breathe and hypoxia have very little relation. So when you feel an immense panic and a very stronge urge to breathe, you very often and in fact most likely are very far from being hypoxic. And in contrary you can have no urge to breathe at all, being deeply hypoxic and blackout without going through any panic state or rush for escape. As long as you do not understand these principles, and do not know how they are triggered, you cannot dive safely. Your exhaling certainly did not save your life at all, did not inject any miraculous O2 into your veins, and it is certainly no backup reserve. The only what it can achieve is suppressing the urge to breathe, which again is dangerous because it can lead to even quicker hypoxia.

Exhaling as a trigger of stronger DR can be _perhaps_ used in case the DR did not really kicked yet in, but it is a highly speculative manoeuvre, and will not work for everyone, and in all situations. The question is whether the reduced O2 consumption through stronger DR outweights the loss of PaO2, so I would really advise avoiding to rely on it as a backup measure.

Thanks for the info. It all sounds really logical! Like I said, I haven’t been using this exhaling technique for many years and in fact I always aboard my dive when I feel like breathing, I never ignore that signal from my body.

However I have also experienced dives where I don’t get the urge to go up for fresh air, really scary actually, and it usually happens after 5 to 6 deep dives.

What are your thoughts of exhaling just 2 – 3 meters before breaking the surface when ascending?

Will this increase the risk of shallow water black out?

Finally, I am not sure about what you mean by “DR” ????