Reg seems to breathe harder when looking up?

[shark.byte.usa]

Sorry don't buy the relationship to the centre of my lungs theory. If that were true then the reg would be harder to breathe when I was vertical head up in the water column when my lungs were below the reg and easier when I was vertical but head down. This is not the case. The difference is only when I am on my back looking up and is not my imagination, the difference is quite noticeable.

Ditto. I'm more apt to believe the diaphram/air rising theory.

Garrett

 

[pescador775]

I haven't used any theory so far, just facts. However, it is time to step off and find out why some bubble divers think their regs breath the same regardless of head up or head down position. Take an example of a diver on deco, suspended at 15 feet, hanging on the line. He notices his regulator breathes a little "harder" than before. For our purposes, assume that the regulator second stage is 6 inches (.5 feet) "higher" than the lungs. The pressure differential is 0.5/48 = 1%. Now, assume another diver is 100 fsw deep doing a super deep stop, hanging, head up same position as the other guy. He doesn't notice any difference in his regulator performance from before. His regulator is also 6 inches (.5 feet) above the lungs. The differential is 0.5/132 = 0.4 %.

Comments welcome.

 

[pescador775]

See next post. Scubaboard problems.
thanks

 

[pescador775]

There is nothing about the regulator itself which would cause significantly harder breathing while the diver is in prone position, facing up. However, having the lungs submerged and lower than the regulator is part of the answer. Enter theory no 2: there is something about the way the lungs operate in a pressure environment which make it harder for the lungs to draw in air while the body is in the horizontal position, face up.

Sometimes, when no answer presents itself, it is necessary to look elsewhere, "out of the box". This is not the same as "making ****e up" which is what the bubble story amounts to.

 

[Luis H]

This subject again.

The physics and mechanics involved in the water column are very straight forward and Pescador and Ratliff are correct. Like Pescador said, “this is not theory”, it is basic physics.

What I do not know is how and were do we “humans” sense pressure during our breathing cycle (since my physiology / medical knowledge is very limited). Also does it vary from person to person (like many other sensations).

The difference in pressure in the water column can be measure (from the regulator diaphragm to lungs or throat, etc.), but that may not be what you are sensing. Knowing were are the sensors associated with breathing resistance could explain this discrepancy.


I can feel the difference when I am vertical head up or down. When I am head up and tilt my head to look up the resistance also increases since the diaphragm moves up in the water column. It doesn’t mater if I am using my Poseidon Cyklon 300 (diaphragm always points to the left) or one of my Scubapro balanced second stages.

 

[Darnold9999]

Don't dispute the theory re lungs - the physics is good. Just its application in this particular case. I don't believe that it is the cause. My reg may breath slightly harder when head down than when head up when I am vertical. Not enough for me to notice however. When I am prone looking up it is significantly harder and I notice - every time.

Note I have not provided a theory as to why, I don't know why, but it isn't the lung position that makes the difference.

Having said all of this now I have to go diving and actually pay attention to this. It wasn't really important now I have to do the experiment.:huh:

 

[Ed Palma]

Can't it be both theories together? I mean, I can see the merits of the water column theory, but I also know what its like to swim on my back (theoretically putting the regulator and my lungs at the same level in the water column). So maybe its a bit of both.

Just my 0.02

 

[H2Andy]

The physics and mechanics involved in the water column are very
straight forward and Pescador and Ratliff are correct. Like Pescador said, “this is
not theory”, it is basic physics.

correct. but i also dispute the application.

i don't think the pressure differential is sufficient to create a noticeable change in inhalation effort depending on whether you are on a horizontal or vertical breathing position.

i sure as heck have never noticed a difference with my regs.

however, i notice a MARKED change from face down to face up position, where the change in pressure is zero b/c i am keeping the same attitude and depth

 

[pescador775]

correct. but i also dispute the application.

i don't think the pressure differential is sufficient to create a noticeable change in inhalation effort depending on whether you are on a horizontal or vertical breathing position.

i sure as heck have never noticed a difference with my regs.

however, i notice a MARKED change from face down to face up position, where the change in pressure is zero b/c i am keeping the same attitude and depth

Uncle Ho, take a ruler and measure from center of your chest to your mouth. What is the distance? Unless you are a Chicago thick neck, like what showed up to "support" the dems during the Florida elections run off, it should be six to ten inches. Ten inches of water columm is approximately equal to three times the cracking effort of the average regulator. Get it?.

 

[bperrybap]

Ok, I do understand the physics involved.
I think that there is more than the lung/regulator
depth differential coming into play.

I have performed this experiment.
2 different regulators, exact same conditions, different results.

Here is the observation
Standing on the bottom of a 12 ft pool.
I'm 6'ft tall so the regulator is at about 6 ft.
I look straight forward and take a breath.
I then I tilt my head back look up and take another breath
and compare.
Looking forward I can breath just fine no problems with both regs.
When looking up, with 1 regulator it is VERY hard to breath.
This isn't a slight increase in effort. No, it becomes impossible
to suck a breath.
The other breaths just fine but breaths very wet.
With 1 regulator the amount of effort increases as the angle
looking up increases until it becomes impossible to suck hard
enough to breath. Like trying to take a breath through a
swizzle stick that eventually gets plugged up.
With the other, it simply starts to beath wetter and wetter.
Also, if I tilt my head to the side even slightly, it makes a big
difference on the regulator that gets hard to breath. It
becomes possible to breath while looking up. It still takes
alot more effort but becomes possible to get a breath.
Neither regulator changes in the amount of effort required to
exhale.


In another experiment.
I have also noticed that if I take a VERY quick short high suction
breath (1 second or less),
my lungs will fill with substantially more air when I am in
a head down position vs a head up position.
This I always attributed to my regulator compensating
for a lower depth than my lungs were it. It seemed to make sense.

The regulators are different styles.
The one that gets hard to breath is a Aeris sport.
The one that gets wet is a shadow+ octo inflator.


--- bill