Discomfort in chest after deep dives

[Mufazalov]

Hi, guys. I just found something interesting after my deep dives. I am doing spearfishing and depths vary, but usually somewhere from 15m to 25m are my normal depths. My absolute max depth (I was without a competent buddy + no gun/light) was 36m and I did it few weeks ago. Since then I was spearfishing pretty deep twice. 1st time was 9 days ago and the deepest was 32m (with 1.5 fins, my omer stingray snapped earlier that day). The day was fine, but afterwards I felt strange feeling in my upper chest, somewhere in the back. I believe its related to the lungs, I am not sure tho. So this strange feeling disappeared only after 2-3 no-diving days.
Yesterday I had a deep water again. My Suunto says I had 45 dives. Starting from number 15 the dives were not very deep:
25m; 23m; 26.5; 24.3m; 21.8m; 24.2; 24.6m; 27.8; 29.8m...
... some mixed dive depths...
Next dives were deeper:
33.2m; 31.1m; 32.7m; 32.6m; 32.8m; 17.5m; 32.5m; then the depths started to decrease (i was kicking back).
I had no trouble with these (luckily my new leaderfins push me confidently thru the water =]) My dive times usually are around 3mins, but almost never exceed 330. During my dives I never did packing. My surface time during these deeps was 4-5 mins.
And today I woke up having the same feeling as I had 9 days ago.
It feels like I have a small ball inside my chest. It doesnt hurt, it doesnt do any bad for my breathing, but I just feel that "it is there".
So the question is: How bad/good is it? I am not sure whether it is something you get after good training (like sore muscles after the gym) or it is a signal that mid 30s are a little more rough than I though? If some of you had the same feeling, did you find a way to "cure" it? Better chest stretching?
THanks for any info.

 

[efattah]

I sometimes get strange feelings in my chest, but usually after extreme packing.

I can't say for sure what you are feeling.

BUT, you are way over the limit for decompression sickness!! If you keep diving with that sort of pattern and those long dive times, you will get decompression sickness for sure... two choices, 1) decrease the depth, or 2) use oxygen to decompress every few dives.

 

[azapa]

or, Eric, greatly increase surface times?

Mufazalov, your dives are certainly deep and long, very impressive, you should try competitive freediving. Did your force your equalization, or did everything go smoothly? 32 to 36 meters is where classic Frenzel fails for me, after that I need to have taken air (mouthfill) or find air (reverse pack). I wonder if you are reverse packing? That is quite stressful if done too hard.

Is it the first time you have been to these depths? Maybe an adaptation issue.

 

[Simos]

Mufazalov - out of curiosity, do you get cold when you dive? Especially at depth?

Eric - how can you tell what the limits for DCS are? Are there any kind of tables for freediving?

Simon - I was expecting longer surface intervals to be an option too but maybe adding a few more minutes of surface time is not enough? Relating to my question to Eric above, it would be quite interesting too to see if there's a way to work out what an adequate surface interval is...

 

[efattah]

I have recently developed a decompression model for freediving, and my Xen computer now does it in real time.

The bottom line is that for bounce dives (down, up, dive time 1'30" or so), longer surface intervals help.

For longer dives (non-bounce) with time spend on the bottom (total dive 2min+) slow tissues start to load, and the surface interval becomes irrelevant. When you start doing long dives (2min+), after a few deep dives you start to need 30-60 minutes or more between dives to make it safe to start the next dive. Oxygen or nitrox is the only real way to accelerate that.

The only other solution is for a diver who has an incredible apnea capacity. In that case, it is possible to exceed the no-decompression limit on every dive, and do a stop at 4m on the ascent for around 30 seconds at the end of each dive. However this greatly increases the risk of shallow water blackout (dramatically!) because you are hanging in the low-O2 zone.

It is also possible to go straight to the surface, breathe for 30 seconds, then immediately go down to 5m and do a deco stop for 1 minute. However, this is a 'bend-and-mend' approach and although it is better than doing nothing, it still tends to produce niggles and other small DCS symptoms if you do it many times per day.

 

[Mullins]

What's your deco model based on Eric?

 

[Mufazalov]

Hey there. Thanks for your insight, guys. I read most of your responses today at 4:45 am, because at 6 we were in the water. I took advantage of our spearfishing trip to try some of the stuff that Eric advised.
We were diving with the boat, spent 6 hours = 41 dives = 2.50 longest; 25.7m deepest.
Eric, Thanks for your tips. I always thought that freediving is very distant from DCS, unfortunately I was wrong. Maybe it explains why sometimes after the dives I felt dizzy.
You said that " If you keep diving with that sort of pattern and those long dive times, you will get decompression sickness for sure." Can you please clarify what do you mean by long dive times + that pattern. What is considered long? Today I wasnt concerned with the times, but with the depth, thus most of my dives were around 20m.

"The only other solution is for a diver who has an incredible apnea capacity. In that case, it is possible to exceed the no-decompression limit on every dive, and do a stop at 4m on the ascent for around 30 seconds at the end of each dive. However this greatly increases the risk of shallow water blackout (dramatically!) because you are hanging in the low-O2 zone."

And only now after numerous times reading your posts I understood the meaning of your words... Its not the depth, but the bottom time that is important right? So I assume that all dives >22m/23m are going to need that deco stop. I thought that it was the depth that played the major role. SO today I did these deco 30s stops only after the dives deeper than 22m. You know, its ehhh... not easy to stay for another 30s on 4m when you are coming up. Instead I used the second thing that you mentioned (kick up >> breath 30s >> 1 minute deco stop @ 5m). Sometimes these 1 minute deco-stops were nice and easy, but after some dives I felt like I was about to have contractions starting shortly after. I cannot bring oxygen with me, so this technique is the one that fits me now...
You also said that, "However, this is a 'bend-and-mend' approach and although it is better than doing nothing, it still tends to produce niggles and other small DCS symptoms if you do it many times per day." What do you mean by "many times per day"? Should I try to minimize my deep dives? What are these DCS symptoms that will be kicking in? I feel like I am getting more confident on deep dives, but maybe I jsut cannot recall whats really going on with my body.
The results were pretty good tho. After finishing the day, I had a lunch+2 hour nap and felt fresh. It might be the mental game that I play(I can easily make myself believe ) or the deco technique used today was pretty good.
Eric, what kind of discomfort do you have in chest? Why does it occur? Is it due to the time down or the depth? I never pack so I dont think that my Discomfort in the chest is related to the extreme pressure added thru packing. I think that it is about the depth (in my case), because every new meter I go (deeper) has some effect on my body, right? When the depth was less than 20 - every meter had an impact on my body but it was not that crucial impact that can easily crush your lungs. When the depth exceeds 25 - every meter is "gently pressing" my body, which has not been as deep before. So its like walking deeper in the woods, knowing that the deeper you go - more wolves you will face. But since the pressure is not increasing proportionally (1atm per 10m,deeper=less) my theory seems to make no sense =] I might be wrong here, heh.
How do you increase depths in CWF/CNF? Do you feel something "new" happening in your body?

Azapa,
"you should try competitive freediving. Did your force your equalization, or did everything go smoothly? 32 to 36 meters is where classic Frenzel fails for me, after that I need to have taken air (mouthfill) or find air (reverse pack). I wonder if you are reverse packing? That is quite stressful if done too hard.

Is it the first time you have been to these depths? Maybe an adaptation issue"
I would love to do competitive freediving, but here in TRNC (Turkish Cyprus) there is no federation that would support this kind of activities. It sucks.
I can still use Frenzel(isnt frenzel= mouthfil?)(and or Valsalva) on 34, but I feel like its about the limit. I usually start with Valsalva and then switch to Frenzel @15-17.
Yes, i use reverse packing to find enough air to perform mouthfill @ below 24m

Simos,
"out of curiosity, do you get cold when you dive? Especially at depth?"
I always try to warm-up before the deep dives. I dive from shore so its a logical way = 4m >> 6m >> 10m>> etc. Yes I do get cold sometimes. Sometimes I am shivering cold. Right now from 0m to 7m the temperature is 31'c (88'F), but below 20s(or 30s)... My face feels tingling. Like when you walk in the snowy (-20'c) weather. I feel like my 5 mm Cressi Tecnica doesnt save me good enough down there.

Again, thanks for all the info you guys posted. I am glad I can read all that right now and not when its too late =]

 

[Simos]

You are cold in Cyprus in August with a 5mm?!? I would have thought it'd be more than enough (I know Cyprus as I grew up there) especially in the summer but I guess it depends how much time you are spending in the water, depth and what time of the day.

Anyway I am no expert but if you get cold (especially shivering) I think it's a bad start for your lungs, I felt some discomfort on my chest before when I was cold and this was at shallower depths than the ones you mention.

Sounds like equalisation could be related too - I'm sure the others will give more info but Frenzel is not the same as mouthfil and if you are reverse packing you are probably not using a proper mouthfil. If you are using mouthfil already, you could try taking it earlier (~15m) and keeping it? I am sure Eric can advise further. Reverse packing could be putting stress on your lungs, depending on how you do it too...

There's an excellent book on equalisation by Federico Mana - I would recommend it..

 

[Simos]

By the way, do you have a buddy watching you closely when doing those deco stops? As Eric pointed out they're quite dangerous - Eric is right that they help with DCS but you really need to appreciate that they're dangerous from a blackout point of view. Probably safer to limit your bottom times.

Also regarding your question on how increasing pressure affects your body - your assumptions on the decreasing effect etc is not the way you should look at it. In fact there are some things you should be aware of with the depths you are now diving too and might explain some things too - look up 'residual volume' in relation to lungs. Apologies if all these are obvious etc

 

[Simos]

This might help a bit:
Lung Squeeze articles/threads

 

[efattah]

Both the bottom time and the depth are important for DCS. At 20m it is very hard to get into DCS danger. At 25m you will get into DCS danger if the dives are long enough and frequent enough. At 30m it becomes easy to get into DCS trouble...

Using the 'bend-and-mend' method of getting to the surface, breathing for 30 seconds, then descending to 5-6m for 1 minute-- the danger depends on whether you are actually violating the DCS rules or not. If you are in a violation on every dive and descend to 5-6m for 1 minute, then if you do this even 3-4 times you might find you get small symptoms later in the day -- it depends GREATLY on the person-- some people are very susceptible, others not, and it depends on how much blood shift you have, how cold the water is, how hydrated you are, etc...

There are too many combinations of depths/time/surface interval to make tables for every possible setup. If you buy a Xen computer the computer will tell you automatically when you are at risk of DCS, and how long you have to wait before going down, and when you had a violation and need to go back down again to decompress. If you do O2 at 6m, you tell the Xen that you switched to O2 and your N2 saturations will adjust automatically. You can also select any nitrox mix (21%-100%) for deco.

The only feature missing in the Xen right now is surface O2 deco. Currently if you breathe O2 at the surface there is no way to tell the computer, but I will add that feature soon.

 

[Simos]

Both the bottom time and the depth are important for DCS.

I took a look at the Xen (sounds pretty cool by the way) and it seems that ascent rate is also an important factor Eric?

Also really glad you mentioned the term 'bend and mend' - for some time now, when I was reading about top freediving competitions and decompression on O2 at 5m/6m, I kept on wondering how DCS doesn't occur since the deco stop was AFTER surface. But the 'bend and mend' term describes perfectly what really happens (which was in line with my thoughts)

 

[Siku]

Eric can you explain what the underlying mathematical principles are for the decompression times? Is there a simple enough method to calaculate without a computer? (As there is with scuba tables.. I was told that the original scuba tables were pretty much uncovered through trial and error!).

 

[Mullins]

Is there really enough data to base a model on? If those diving patterns represent a high risk of DCS, there must be dozens of severe DCS cases in freedivers around the world every year. To use myself as an example: I'd typically consider a pattern of 2:00 dive @ 30m / 3:00 surface for a couple of hours to be pretty conservative and many others would too. In the tropics it'd be a bit deeper & longer. Shouldn't there be a DCS epidemic? I'm not necessarily saying there isn't, because I'm not really in touch with the spearo scene in the Med. and NZ divers typically don't go very deep.

 

[efattah]

I think there IS a DCS epidemic, except that the freedivers don't realize they are getting bent. Look at Branko Petrovic, for example, DCS after every dive session but he didn't realize it.

For most divers, most sessions would only result in minor symptoms; slight transient pain in joints, transient tingling or numbness in fingers or toes (often confused with numbness from cold), as well as major fatigue over the next 24h (often confused with exhaustion, dehydration, sun exposure).

Getting paralyzed from DCS takes a more aggressive profile, but not that much more. Herbert collapsed from DCS paralysis after 9 dives, 35-45m, 2'30"-3'30" in length, 6'30" surface intervals. One of my more severe cases was also after 9 dives, 25-38m, 2'44" average dive time, 6'30" average surface time. My worst DCS case came after 8 dives, 32-51m, 2'25" average, 8 minute intervals. There is a HUGE difference between repeated 30m dives, compared to repeated 40m dives.

In my case I correlated and tweaked the model with my own symptoms (a dozen minor DCS incidents) as well as with other divers and the common rules for deep dives. The results matched incredibly well. I am however rather susceptible to DCS, so the model may be a bit conservative for some people, but better safe than sorry. Anyway the Xen allows to you modify the conservatism (though we might remove that option later for liability reasons).

For single max dives, the model predicts that no deco is necessary for 70m dives if the ascent rate is reasonable. 80m may require deco depending on the dive time. 90m requires significant deco, and 100m requires deco starting at a depth of at least 9m, perhaps as deep as 21m. This also correlates with my own experience, since after the 104m in the Bahamas, I did O2 for 5 minutes at 4.8m and still got minor DCS symptoms. My gut feeling was that 4.8m was not deep enough, and that I need to start the deco much deeper (to crush the bubbles), on a lower mix of O2, then move up to 5-6m on 100% at the end. Plugging in my 104m dive, the model says I need to do a 1 minute stop at 9m on 80% O2, followed by 7 minutes at 6m on 100%. However if I tell the model that I have access to 50% O2, it then calls for a 1 minute stop at 21m on 50%, followed by 4 minutes at 6m on 100%.

 

[jay cluskey]

this thread has certainly opened my eyes thanks guys

 

[Andrew the fish]

Theoretically, for shallower dives like 30 meters or so, one does not need packing, and having smaller volume of air in lungs would probably mean less nitrogen dissolved. I am just thinking of any other inexpensive fix, something other than mending.

 

[efattah]

Theoretically, for shallower dives like 30 meters or so, one does not need packing, and having smaller volume of air in lungs would probably mean less nitrogen dissolved. I am just thinking of any other inexpensive fix, something other than mending.

Unfortunately taking less air down had no effect for me. After my first bad DCS incident with packing, I switched to FRC diving for the main reason of avoiding DCS. Across four years of FRC diving, I got DCS all the same in the same ways and same depths. My conclusion: lung volume made no difference. The only thing was that on FRC dives, being somewhat shorter in duration, the exposure time was a bit less.

 

[Mufazalov]

Hello guys, its been a month since the start of the thread and I ve had enough time to put some of Erics' advices to the test.
These days I do feel much better at depths, because last month most of my diving was oriented towards greater depths. My PB is still 37m (no gun, bi-fins, the dive itself was around month and a half ago), but I feel much better now diving to 30s (spearfishing).
This month our dive pattern changed. I go spearfishing Mon/Wed/Fri/Sat and on my free days I go to the gym to get back in shape. We shore dive, but as I said earlier, I spent most of my time at around 30m deep. Dives up to 36 are very smooth, I am able to do up to 2 minutes aspetto (waiting on the bottom), so the dive times are around 3min. 35/45 secs down, aspetto, 20/25 seconds up. During the day I am doing around 60/70 dives, 20-30 of them are to around 30, Apnea time per day is usually around 1:30/2 hours.
As far as my deep-diving DSC concerns go, I feel pretty good. I am able to maintain that "30 secs breath up, dive to 5m for a minute" after dive habit throughout the day, I dont do it when the dive is <25m or <2:00 long. And I think that the results are great. In my posts I said that every day of diving was followed by severe dizziness, blood pressure jumps, overall exhaustion. Most of the symptoms have been eliminated (exhaustion is still there, but that's logical).
Again, maybe it was simply an adaptation issues, maybe these were the symptoms of DCS, but seems to me that these days most of them are gone.
So I advice you guys to try the same deep-dive decompression tricks, check whether it will make your diving days a little easier/safer. Eric and all others, thanks for the input.
Dive safe.

 

[Mullins]

Ascent rate of 1.5m/s with bifins? That's pretty quick...