Why depth feels nice but dynamic feels horrible?

[Kray]

I never had access to pool, I dive exclusively in the ocean. What I don't get is on my depth dive to 70-80m with monofin, on the way down I try to kick as far as I feel comfortable, usually 23-26 kicks possibly gaining 40-50m before freefall. At the bottom, always feel nice like I could hang for another half a minute. On ascent I might get a few contractions starting around 30-20m. Two recovery breaths at surface, nice easy dive. However, every time I try to swim horizontally with no glide to simulate depth diving, I can only manage like 25 kicks, contraction begins, feeling so horrible that I can no longer continue. So, question is what kind of MDR that takes away the shitty feeling when we dive deeper. I don't recall instructors mentioning it on my beginner course. On my depth dive, I probably make between 55-70 kicks in total not to mention static when freefall. There is just no way I can swim this much horizontally. How do you explain it?

 

[Davos]

I feel like there might be some physiological differences. A stronger or more advanced dive reflex in depth dives?


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[Davos]

Err, sorry that was your actual question. I'm silly and didn't read it properly.


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[Kray]

Ha. No worries. Do you feel the same?

 

[Davos]

Yeah, totally. I never feel comfortable in the pool. Every metre hurts haha


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[Porky Pig]

Yep, agreed. Pool is completely different and so much more painful, but I am not sure why.

 

[derelictp]

Same for me. I belive there is several reasons:
-Relaxation is better in CWT because we do not have to manage bouyancy/position in depth problems which is more or less taxing.
-The oxygene consumption seems more dependent on how much energy we use early in a dive. In CWT we can use ATP before the aerobic process is starting and then we use the freefall that is lika a STA. When we arrive at the bottom the dive reflex i strong which inhibits the aerobic process on the ascent.

 

[Kray]

I suspect the blood shift. By increasing blood in alveoli combining with the concentration of O2 making us feel super fresh at depth. But they say Co2 is the trigger of the contraction. The concentration of Co2 also rises. So could it be that it's the volume of Co2 that matters? Because for me, the contraction always comes at the last part of the dive when gas expands.

 

[cdavis]

Blood shift is probably the main factor. Its much stronger in depth diving than dynamic. On a deep dive, blood shift greatly reduces the blood return from the skeletal muscles. The co2 stays in the muscles and away from the co2 sensors in the chest that make you fell lousy during dynamic.

 

[Kray]

Make sense. According to Google, aenarobic exercise in human does not produce Co2 but lactic acid. So after blood shift, the mdr is fully on, making it possible to propel from the bottom without much suffering from Co2. Once the lung expand above RV, mdr lessen, then we start to feel contraction from aerobic exercise.

 

[Davos]

You make a valid point. Of course, the use of energy systems isn't black and white - it's a combination of systems (a 100m sprinter might have an 85/10/5 split, for instance).
I would be very interested to see how these systems are used across the two disciplines. It makes sense we'd be using more muscles more often in a dynamic, so you're probably on the right track.


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[cdavis]

Davos, there is a very interesting article on www.freedivewire.com that goes precisely to how energy systems work in combination

 

[Davos]

Davos, there is a very interesting article on www.freedivewire.com that goes precisely to how energy systems work in combination

Thanks for the link. That lines up with roughly what I thought. Very interesting stuff.


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[MarcinB]

Decreased peripheral chemoreceptor sensitivity to CO2 resulting from hyperoxemia is likely a contributing factor too. During deep diving pCO2 in lungs increases much less than pO2. Psychological factors may also be important here, if you don't train in a pool at all, you won't feel as comfortable there as in the ocean.

 

[onefasteuro]

Partial Pressure of O2 in the Ocean is way higher especially at the depth that you are mentioning hence that feeling of comfort, which comes off as you make your ascent. the the pool, there is barely any changes hence the "discomfort" that comes earlier.

 

[frank merrritt]

I never had access to pool, I dive exclusively in the ocean. What I don't get is on my depth dive to 70-80m with monofin, on the way down I try to kick as far as I feel comfortable, usually 23-26 kicks possibly gaining 40-50m before freefall. At the bottom, always feel nice like I could hang for another half a minute. On ascent I might get a few contractions starting around 30-20m. Two recovery breaths at surface, nice easy dive. However, every time I try to swim horizontally with no glide to simulate depth diving, I can only manage like 25 kicks, contraction begins, feeling so horrible that I can no longer continue. So, question is what kind of MDR that takes away the shitty feeling when we dive deeper. I don't recall instructors mentioning it on my beginner course. On my depth dive, I probably make between 55-70 kicks in total not to mention static when freefall. There is just no way I can swim this much horizontally. How do you explain it?

Maybe it is because in the pool, your mind knows that there is air just above you, so it wants you to surface NOW, but at depth this is not an issue.