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So going over my dive i am absolutely astonished that i improved my SAC rate on this dive to anew record low. My SAC rate was already insanely good, but now... Wow. The dive instructor/guide who was with me said "I've never seen anyone with a SAC rate this low". My SAC rate was 0.4 cubic ft. Per minute (11.3 liters per minute). Most tec Scuba divers have SAC rate of 14 - 19 liters per minute.
Here is the link to my dive profile to check it out:
@freemo Does that basically mean you can stay underwater a lot longer than the average diver?
@trinsec
Sort of. IF both me and the other diver are at the same depth, then yes, incan stay there much longer. However if i go deeper then i will use my gas up much much quicker. So if the depth is different then it depends on the details.
@trinsec
SAC rate is basically just how fast i breathe air (the volume of air i breathe). So having a low sac rate just means i breathe very little air.
Wikipedia says, "After exhaling, adult human lungs still contain 2.5–3 L of air, their functional residual capacity or FRC. On inhalation, only about 350 mL of new, warm, moistened atmospheric air is brought in and is well mixed with the FRC."
But when I experimentally exhale into a bag I get what looks like about 2-3 L.
So, at 2.5 L per breath, that puts you at about 4.5 bpm (breaths per minute), which is low. (WP says adult normal range is 12-16, mine is usually <10 bpm at rest.
With different mixtures, I'm sure that throws the whole thing off, because more O2 would mean lower bpm for the same amount of CO2 produced, I think.
What does SAC mean?
@Pat
At depth despite still breathing 21% o2 in this case the increased pressure means it has a partial pressure of 1.4 which would be equivelant to breathing 140% O2 at surface. So yea. Also nitrogen narcosis slows down the system and likely helps me breath a bit slower.
SAC means "surface air consumption" its basically the rate you breathe at.
@trinsec
Yes, that's probably true. Also, it says, "..air is brought in and is well mixed with the FRC." Some air remains in the upper respiratory tract, so that amount probably wasn't in their figure.
Regarding intentional vs relaxed breathing, I noticed that you can't very effective measure your own breathing rate/volume because simply being aware of it effects the breathing and results.
It's kind of like trying to tickle yourself, it doesn't work.
@Pat @trinsec
Also my guess as to your breath volume... You were probably trying to fully exhale when you were doing it. Wikipedia is probably talking about a typical breath youd make when relaxed, which is much shallower.