Contractions not due to CO2 build up but to reduced lung size

[Cassin]

Hi all,

I'll be glad to have some comments on a problem I have. I get contraction starting as shallow as 10 meters on my way down.
I was thinking that it arises too fast to be caused by CO2 build up . So i did this experience :

Start to dive down, and when i feel the first contraction I stop, turn around and when I surface I keep the breath hold for some time. I am so surprised to see that I have no more contraction on the surface for around 20 /25 seconds

So this means that contraction can also be caused by the fact that the lung volume is lowered. Nobody told me about that before.

I still manage to dive down to 52 meters CWT with bi fins but the contractions make it a lot more difficult to equalize, and also I am worried for the squeeze that can happen more easily with contraction.

If you have any idea on how i could get rid of this kind of contraction ? Or more realistically, any comments on how I could deal with those contraction ?

Cheers

Ps : in general i do get contraction quite quickly, around 1:30 in static for example. Which doesn't bother me cause they are mild and I believe that for static (and dynamic) it's not a bad thing actually.

 

[Apneaddict]

It's likely a "pressure trigger".

Solution: more time at depth / under pressure combined with some appropriate stretching exercises for the diaphragm (uddiyana) and also for thoracic flexibility.

Let the pressure be your friend, instead of having your body resist it.

 

[cdavis]

You are correct that contractions can be caused by lung compression, not uncommon. When I first started diving deeper, approaching RV, I used to get those. As Apneaaddict said, time and practice usually take care of it, although they can come back when you push your normal depth. I found that, once I realized what they were and relaxed, mostly they disappeared. Stretching also helps.

 

[Vov]

Increase depth gradually - from dive to dive... start with small depths, relax, enjoy...then gradually increase. How gradually - you will have to find out yourself.

 

[Will]

I don't think these contractions are due to lung compression. If this was the case you would get them stronger with exhale dives, and they would not go away during a hang at depth.
Rather, I am convinced that the contractions are due to a rapid rate of change in ppCO2. There is a lot of evidence that supports this, but the easiest test is depth training tables. During these you can get contractions as early as 5-10m, but they will normally subside in the ascent.