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Lung squeeze

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Well-Known Member
Nov 7, 2001
Hi All,
My brother has been in training for Cyprus, and around a month ago he started to have a chest pain, but not severe. It was only in deep inhalation. He started to take Ibuprofen. With the time it get more severe. After that he felt nasal swelling, throat pain, and malaise. He continued with his training, and in depht he felt better but at the end of training he felt bad again. As the chest pain get worst, he felt tightness in the chest, and the pains moved toward the upper part. He describes the feeling like if something don't let him to full fill his lung. All the symptoms persisted despite huge amounts of Ibuprofen and Aspirin.
His training consisted in several constant ballast descents over 50 meters with 10-30 seconds hangings for 2 days, after 5 resting dates, he trainen empty lung dives around 23-25 meters (6 times) for 2 days. 5 days resting. Due to the chest pain he continued his training but at 10 meters with reverse packings (15) 12 times. After a 10 days resting period he tried a 70 meters immersion, but at 10 meters a severe chest pain make him abort the dive. With all this problem he noticed a severe compromise of his static time too.
I think he had suffer a lung squeeze, and we want to know if someone has experienced something similar. BTW he had never experiences bloody cough.


Well-Known Member
Mar 2, 2001
Hi Frank,

It definitely sounds like your brother experienced lung squeeze. It is unfortunate that he did such strong negative pressure dives. Doing a full exhale negative pressure dive to 10m already simulates over 80m of depth, and there is little reason to go deeper unless you are training for no limits -- going any deeper just increases the risk.

Also, he is very lucky he didn't get decompression sickness from doing hangs at 50m! This is very dangerous!! When diving over 50m, no time should be spent waiting down there, and if you do wait, you must take a long surface interval (20min+)!!

I think your brother should see a doctor -- hopefully Laminar will respond as well but the usual treatment is simply no diving for several weeks, and no deep diving (or negatives) for several months...

Eric Fattah
BC, Canada


Well-Known Member
Aug 13, 2001
Hi Frank,

Sorry to hear about Karl. There was a scientific study that linked aspirin/ibuprofen to pulmonary edema. But it was only one study, and I don't know if it was backed up by other research. I can ask my few contacts about his case, though.

Although I'm not a doctor (Karl should definitely see one!) I would say he should stop diving now. I think time at depth is a major factor in causing a severe squeeze. It's odd that he experienced no blood coughing, but that doesn't mean other parts of the lung, bronchi, and sinuses weren't harmed.

Not only that but one thing you should be aware of--I mentioned it in the article--is the significant and relatively unknown effect of negatives, packing and deep diving on the heart and circulatory system. Symptoms like pain in the chest are often indicators of heart/curculatory trouble under normal circumstances. Maybe the pain he felt wasn't in his lungs at all.

Pulmonary edema in non-diving cases is often caused by circulatory problems caused by other medical conditions. Given that your brother was doing massive negatives and long hangs (long durations below residual volume) this could have caused the heart to work overly hard. I am no heart expert, but I'm sure a cardiac specialist could make a long list of the stress that kind of training regimen would put on Karl.

Karl should stop diving, hope that whatever has happened heals so that he can do a nice static in Cyprus, and maybe even skip the diving all together. In my experience, it took at least 3 weeks to stop feeling symptoms out of the water, and 6-8 weeks before I felt normal underwater again. In Karl's case, I don't know that that would be enough. Again, seek medical advice, hopefully from a specialist.

Pain in freediving is a sure message that whatever you're doing is wrong. Taking pain-killers is not the way to go!


Be safe Karl!

Vancouver, BC

Fred S.

New Member
Sep 22, 2001
Eric F. wrote: "Doing a full exhale negative pressure dive to 10m already simulates over 80m of depth"

Eric, could you please give me the formula to calculate these simulative depths??



Dairyland diver
Apr 7, 2001
I am certainly no doctor and wouldn't pretend to be one.

But, the fact that he has no blood coughing I find interesting. Since he also has malise, tightness in the chest, has been doing statics at 50m, feels good at depth, feels worse after training and can't seem to get a full breath makes me wonder if he isn't just bent?

Many of these things are also present in decompression sickness. Has he seen a DIVING doctor yet? I have heard too many horror stories about bent divers going to see a non-diving doctor and not getting treated properly. In one case that I know of, the diver called down to D.A.N. while he was in the waiting room so that D.A.N. could call the hospital and get him the correct treatment!

Hope all goes well and he feels better!



Well-Known Member
Mar 2, 2001
Assume vital capacity = VC
Assume residual volume = RV
then total lung capacity = TLC = RV+VC
all calculations assume ideal gas law at depth, which is not very accurate

Now, during a negative pressure dive, the diver begins the dive with RV litres.
During an inhale dive he begins with RV+VC litres.
During a negative dive, the final lung volume is RV/K, where K is the pressure factor.
During an inhale dive, the final lung volume is [RV+VC]/K, where K is the pressure factor.
Suppose we want to simulate an inhale dive to S metres.
The pressure factor K = (depth/10)+1 = 1+ S/10
The final lung volume is [RV+VC]/K = [RV+VC]/[1+S/10]
Now, what negative pressure depth N must the diver go to to reach the same lung volume?
The final lung volume on a negative dive will be RV/K, where K = [depth/10]+1 = [N/10]+1
Final lung volume on this negative is RV/[ 1 + N/10 ]
We want the final lung volume on the negative to be equal to the final lung volume on the inhale dive to S metres.
So, equalizing the two lung volumes
[RV+VC]/[1+S/10] = RV/[ 1 + N/10 ]

Solving for N gives
N = 10*[ [RV*(1+0.1S)/(RV+VC)] - 1 ]

So, suppose I wanted to simulate 80m of depth, and for me RV=2 VC=10
the required negative depth N is
N = 10*[ [2*(1+8)/(2+10] ] - 1 ]
N = 10*[ 2*(9/12) - 1 ]
N = 10*[ 18/12 - 1 ] = 5m

Let's check the answer.
At 5m of depth at full exhale, my lung volume would be RV/K = 2L / (5/10+1) = 2 / 1.5 = 1.33L
At 80m of depth, my lung volume would be RV+VC / K = 2+10 / (80/10+1) = 12 / (8+1) = 12 / 9 = 1.33L

So, I to simulate 80m of depth I need to do a negative to 5m. There are two other factors to take into account. At depth, the gas is non-ideal, which slows the compression of the lungs. The blood shift also happens. During the negative, there is not much time for the blood shift, which makes the negative even more extreme than it seems. Both of these factors imply that for me to simulate 80m, I would need to dive to less than 5m. And, from experience, at 80m it feels like a full exhale dive to 5m.

One last example. Suppose the diver has RV=3L, and VC=7L. He wants to simulate 90m.
N = 10*[ [3*(1+9)/(10) - 1 ]
N = 10*[ 3-1 ]
N = 10*2 = 20m

So, this diver with a huge residual volume and smaller VC (perhaps no packing), would have to do a full exhale dive to 20m to simulate 90m. Yet, we have seen that this formula predicts a too aggressive depth. So I think it is safe to say that there is never any reason to do a full exhale negative of 20m.

Doing reverse packs might result in a required depth of only 2m!

Eric Fattah
BC, Canada


New Member
Dec 7, 2001
How about Seb. Murats diving technique? He makes his constant weight dives on empy lungs.


Well-Known Member
Nov 7, 2001

Hi all,
Thanks for all the input.
My brother is here now, I'm an Internal Medicine Specialist, and fellow in Pulmonary Medicine.
I think you're right. The stress is not only on pulmonary, but also in cardiovascular system. The fact that he doesn't suffer blood coughing is strange, but doesn't rules out the lung squeeze. The DCS is another possibility but doesn't explain all the symptoms. Both things?.
I will make some tests to find out how is pulmonary and cardiovascular system.
I'll let you know how things go. - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing


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