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Danger in ascent?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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Jay Styron

New Member
Aug 31, 2001
Just wondering if anyone else found any flaws in Eric Seedhouses article? If it was dealing w/ scuba I'd totally agree, but not freediving. Maybe I just read it wrong?:confused:
article maybe useful

My impression was that pulmonary barotraumas could happen in freediving from making an ascent to fast. Quote: “A free diver not exhaling during an ascent or making a fast ascent will cause their lung volume to expand rapidly. If the ascent is too fast then the musculoskeletal cage may exceed its expansion limits.” But of course this flies in the face of what I do, that is ascend almost as fast as I can.

I think you are right in that there is more danger in scuba, because breath pressure is ambient at depth which makes more volume of air to expand on assent. But with a very large final breath, and especially packing, you maybe able to get more volume of air in the lungs than can handle a rapid ascent.

I have also heard that this rapid increase in lung pressure may contribute to SWB. Some of the people who were saying this suggested that when you pack and dive deep, let a little air out at about 20’ from the surface on your ascent. I’m definitely no expert, but with the little information I have, it seems like doing this is a prudent thing to do for now. If someone proves this wrong, then I will change. At 20’ or less from the surface in the ascent, most of the oxygen has already been extracted, I’m only seconds from the surface, and letting a little out eases the pressure and is a little more comfortable.
Thanks Ben, thought I just wasn't reading it right.
Don, it just seemed to me that the article was relating more towards the physical damage of over inflation. In freediving your lungs won't expand anymore than on the surface w/ your last breathe up. I can't say for sure but I think you can expand/fill you lungs faster on a good,quick,deep inhalation than what you would experience coming up from depth. I haven't heard of anyone blowing out an aveoli from packing, there has to be an "outside source" of air at depth to over pressureize the lungs and cause rupture on ascent. You could be right physiological stuff. I just don't don't think that was the premise of the article.
Yeah, I definitely don't agree w/ what he's saying. :(

Your statement: ”but I think you can expand/fill you lungs faster on a good,quick,deep inhalation than what you would experience coming up from depth” might be correct. I know for me that when I do more than a couple of packs, the pressure makes me a little uncomfortable, until I get about 10 feet down. I get the same uncomfortable feeling if I don’t exhale a little before returning to the surface, plus it’s on top of the low O2 high CO feeling. If its possible that letting a little air out lowers the chance of a SWB then with the increase in comfort, its more than enough reason for me to do it.

I agree with you and the other people too. Most of the article seemed like it was trying to relate known medical problems that occur in scuba to freediving, when there wasn’t much similarity, just to have something to write about.
Real Danger

I have heard of at least one case of a freediver suffering severe injury due to embolism on the ascent, but it was years ago and I can't remember much about it. Spearfisherman I think.

On my first two days of freediving, my chest was very inflexible, and even without packing, on every ascent air would explode out of my mouth in the last 2 metres. It was pretty scary.

These days, if I pack to the max, I always need to exhale a bit in the last 1-2m. The danger is far greater on shorter dives. During long dives (or long statics on the bottom of the pool), the lung volume shrinks due to CO2 dissolving in the blood/plasma/tissues. If I pack to the max, go down to 2m, and then come up without exhaling, I would almost certainly suffer injury. The main reason is that I pack 3 litres over my max inhale volume, and to get those 3 litres requires an extremely strange body position (back extremely arched, shoulders way up, head cocked way back, belly out). If I am not in that exact position, my lungs/rib-cage cannot handle the volume. Once I get down to 2m, I don't need to assume that position anymore. Then, if I (immediately) ascend in a 'standard' relaxed posture, that posture is incompatible with the volume of air in my lungs. What would probably happen is the air would come bursting out of my mouth (if I didn't exhale on purpose), but if I slammed my throat shut, you would probably hear a loud 'boom' (like a sonic boom) as my chest detonated from the pressure. There would be pieces of me everywhere!

Just remember that the greatest danger you can ever put yourself in is to pack to the max, and go down to the bottom of the pool, and then 'abort' the static and re-ascend without exhaling.

Eric Fattah
BC, Canada
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Before I throw out the article, let me throw out a what if;

How fast does the blood shift, unshift? If you have a 7 litre container, pack in 8 litres of air and take it to -50 meters and a one litre blood shift occurs, couldn't you end up on the surface with more than you started? Maybe the last minute relax, look up and exhale routine is important.
My reasoning comes from a repeated observation of neutral buoyancy. I am more buoyant on my first dive than any other (unless I pack). Of course, that deals with many variables.
Just wondering.
On a related subject, can any one help with this 'mouth full of air' technique? I can go from surface to -14 on a mouthfull but not from -30 to -60.

P.S. I write slow. I didn't see Eric's contribution.
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I think what's been said in the article can only apply to the case of a freediver with packed lungs and not using a mask. Apart from this scenario (which has also been discussed in the Failure Depth thread) I really can't see any significant risk? Otherwise wouldn't we all be suffering from barotrauma right now?? The above case probably doesn't apply to many freedivers, since the vast majority of freedivers use a mask. And those who do fall into the above category (noseclip) have figured out for themselves that it makes good sense to exhale a little before surfacing to protect their lungs.

Not Sure

As I mentioned, the first few days I freedove, I didn't pack, and I was using a mask, and air would explode out of my mouth and nose on the last 1-2m before the surface--but only because my throat was relaxed.

I think this problem affects people with inflexible rib cages (especially in their first few days of diving).

Eric Fattah
BC, Canada
Not usual but real

We have to remember that a mucus plug can "aisle" some bronchi from the rest and in that way it's possible a barotrauma. I read an spanish article about the intrathoracic hypertension syndrome in a breath-hold diver, he suffered pneumomediastinum and pneumopericardium, and he doesn't pack at all and the depth was around 15 meters.
This is by far more frequent in SCUBA divers.
This is the link: http://db.doyma.es/cgi-bin/wdbcgi.e...?inctrl=05ZI0110&rev=2&vol=111&num=20&pag=798
Mucous Plug

I've heard of this before - but why would you have mucous in your alveoli? Don't the bronchial cilia prevent such fluids entering the lungs? Also, the presence of surfactant should reduce any likelihood of 'stickiness'. If this has been reported in breath hold divers - has it not also been reported in non-divers who might get it whilst breathing on land?

The point being, that it is so remote/ unlikely that it isn't significantly different from being on land - other than the packing case that Alun, Eric and myself have discussed (albeit separately!) already?

It's possible

If the cilias was as efficient as you think the human beings will never suffer or pneumonias or bronchitis. They aren't so efficient, in fact many of the atelectasis (local lung colapse) are due to mucus plug, thats one of the reasons to avoid diving with a cold, the surfactant help us to reduce the superficial tension and also has immunologic activity but it can't avoid the mucus plug.
The case reported in the link of my previous post is from a freediver who suffer a barotrauma.
When you are breathing on land, you are not suffering such a big change in pulmonary volumes as in freediving. The barotraumas in people at land is due to high pressure due to other reasons (cough).
Any way that is very rare to happen in freedivers, but it can
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Re. Mucus plug .
Remember that there are spearo's who smoke ..., strange but true .
I used to puff around twenty a day and still spear comfortably over -30 m. Someone in this situation could easily suffer a blockage .
Would assume that most non- packing spearo's needn't blow off before surfacing since some air from the lungs is lost due to mask equalization .

This article sure made me wonder.SWB to me was always the main obstacle to the big blue and something to watch out for. After reading this article on barotrauma, I felt like most of you guys wondering. I read again some articles on the subject I had from DAN , they don't mention freediving , scuba is of course mentioned as a lot of scuba accident have to do with pneumothorax or lungs overexpensions...rupture.
Anyway I have never heard of a freediver having such a problem, and it seems that you guys didn't either. Lets just be conscient of the risk without creating a fear factor around it...
On the other end I remember reading in this thread, somebody mentioned that lungs problems could be linked with SWB...that would be worth investigating if that is proven to be true.

catch you on the other side...

I think that the article is well written. For the most part, the information is accurate. I would like to see the sources that were used to formulate such an article. I think that there should be refrences for the readers to expand thier knowlege base and make refrences to. I also would have liked for the author to put the disclaimer as to who the most succeptibles are in the beginning of the article, not at the end. I believe more thought should have been put into editing the article than anything. As for the content, it was acceptable.