Is oxygen consumption depends on the depth and can we count it?

[stuartv]

Would be better to be working in mass, moles, or volume at standard temp and pressure. Percent is not an appropriate unit, saying you are metabolizing 4% is causing lots of confusion and inaccuracies.

I'm not using percent as a unit. Did you read my explanation? My units are units of volume, as I specifically stated. If you personally breathe 10 liters of gas in a respiratory cycle, then my "unit" is 1% of that or 0.1 liters.

Were YOU guys actually confused? I mean, confused by the end, versus just momentarily confused at the beginning? Or are you just expressing straw man confusion?

 

[tbone1004]

I'm not using percent as a unit. Did you read my explanation? My units are units of volume, as I specifically stated. If you personally breathe 10 liters of gas in a respiratory cycle, then my "unit" is 1% of that or 0.1 liters.

Were YOU guys actually confused? I mean, confused by the end, versus just momentarily confused at the beginning? Or are you just expressing straw man confusion?

I was confused by this part. The math you presented is right, but the sentence quoted below is the confusing part.

* I am defining 1 unit as 1% of the volume you breathe in and out at the surface.

 

[stuartv]

I was confused by this part. The math you presented is right, but the sentence quoted below is the confusing part.

* I am defining 1 unit as 1% of the volume you breathe in and out at the surface.

I edited my original post to explain that in more detail. I hope that helps prevent confusion among future readers.

 

[rjack321]

I'm not using percent as a unit. Did you read my explanation? My units are units of volume, as I specifically stated. If you personally breathe 10 liters of gas in a respiratory cycle, then my "unit" is 1% of that or 0.1 liters.

Were YOU guys actually confused? I mean, confused by the end, versus just momentarily confused at the beginning? Or are you just expressing straw man confusion?

I was talking to the OP about thinking/using "4%" as a unit of consumption

 

[Miyaru]

@stuartv I totally agree with you from a physics point of view, when it comes to ongassing, offgassing and partial pressures.

...
Yes, your body is holding more O2 at depth. But, even though you have more in you, you still only metabolize the same amount.
...

I would be careful with such a statement, my medical knowledge isn't enough to answer to that.
There's a biological part as well and I'm not sure if (unused) oxygen is simply returned from the tissues to the veins and to the lungs for off-gassing.

 

[Barmaglot]

Are we even capable of metabolizing oxygen dissolved in blood plasma as opposed to the oxygen attached to hemoglobin?

 

[Miyaru]

Are we even capable of metabolizing oxygen dissolved in blood plasma as opposed to the oxygen attached to hemoglobin?

Yes! Hyperbaric Oxygen Therapy (non-DCI treatment) is based on this principle. Surviving CO poisoning as well.

 

[lermontov]

Are we even capable of metabolizing oxygen dissolved in blood plasma as opposed to the oxygen attached to hemoglobin?

there would have to be some by diffusion even if only a small %

 

[fsardone]

@stuartv I totally agree with you from a physics point of view, when it comes to ongassing, offgassing and partial pressures.

I would be careful with such a statement, my medical knowledge isn't enough to answer to that.
There's a biological part as well and I'm not sure if (unused) oxygen is simply returned from the tissues to the veins and to the lungs for off-gassing.

In order to understand this think to the blood as a conveyor belt. It picks up oxygen at the lungs and brings it all around the body. If oxygen is needed it is used by the cells, if not it stays on the conveyor belt.
When the coveyor belt goes back thru the lungs, if there is space available on the conveyor belt additional oxygen is loaded, otherwise the conveyor belt keeps going.
The only case oxygen might be released (but it wont because it would have been used well before returning to the lungs) would happen if you reduce ambient pressure and make the plasma supersaturated ... when in the lungs. it does not happen.
The conveyour belt has two ways of carrying oxygen:
- slots that can carry one O2 molecule bound to Fe in hemoglobin (the amount that can be carried is fixed and does not vary with pressure, only depends on how many red cells you have)
- free dissolved in plasma (amount is function of pressure the higher the more dissolves in plasma).
At high pressure all the slots are and remain occupied by O2 and the exchanges happen with the O2 in plasma. At low pressure the plasma carried oxygen is insufficient to satisfy metabolic needs and the hemoglobin bound O2 is also used.

Very approximative but I hope I gave a model to understand it.

As others before me said, the amount of oxigen used by the body at a given effort level does not vary. Meaning: the number of moles (mass) of O2 used in a time unit stays constant. A mole of O2 contains the Avogadro number of molecules (the molecules are used in the chemical reactions and therefore the number of those used change only if you i crease your effort or need to generate more heat to stay warm). If you want to know how many liters or bar (or whatever unit of your choice) use the PV=nRT gas state equation where n is the number of moles P is pressure V is volume and T is absolute temperature. R is a constant that depends of the unit used.
Basic 10th grade physics and chemistry.

Cheers