How much air do you keep in your lungs most of the time?

How full you keep your lungs when diving?

  • 0-25%

    Votes: 1 5.0%
  • 25-50%

    Votes: 9 45.0%
  • 50-75%

    Votes: 8 40.0%
  • 75-100%

    Votes: 2 10.0%
  • 100%, I'm a mad pufferfish

    Votes: 0 0.0%

  • Total voters
    20

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I don't understand the poll. I take long, slow, even breaths while diving. Not that much different that when I'm sitting on the sofa watching TV. So, what exactly are you trying to determine with your poll?
 
people do a small and a big pause between inhaling and exhaling. at least for me the small pause is after inhaling before exhaling, and the long pause after exhaling before inhaling again. My lungs are thus rather empty most of the time, let's say about 25-50% full. The question is how is this for other people... is it a dumb question?

My question was motivated by this video:



the guy is diving normally at depth X and start ascending just by using his lungs. You can do that only is you are diving with rather empty lungs, otherwise you have to overinflate them, which isn't advisable when you are ascending.
 
No ... you don't need empty lungs to do that. No more so than you need an empty BCD to begin an ascent by putting air in your BCD. Think of your lungs as just another, smaller BCD. You just need it to not be full at the beginning of the process. You breathe in to start yourself upward, and as soon as that progress begins, you can breathe back out again. As you rise, all the air spaces on your body ... BCD, drysuit, lungs, mask, wherever else you have air ... start to expand. As they expand your ascent will accelerate until you release a bit of air to control the ascent rate.

You don't need to retain any air in your lungs at all ... just continue to breathe as you normally would.

... Bob (Grateful Diver)
 
Trick question. The answer is "any of the above" depending upon the buoyancy you need.

DIR style divers are trained to use their lungs for micro-buoyancy adjustments, so you breathe in the 75-100% range when you need to ascend slowly, and in the lower range when you need to sink. Adjustments to your BC and/or drysuit inflation follow this if you need to maintain your current buoyancy for a longer time.

I worked it out for myself in the pool, and it's not even that "micro": my range between breathing with full lungs and empty lungs is 6 pounds of buoyancy. Which is to say if breathe close to 100% full, I can lift a 6lb weight from the bottom to the surface, wearing just my swim trunks.

That's a pretty nice range to get without even touching your BC inflator. Learning these techniques can save you a lot of futzing around with BC buoyancy = more time to attend to other things during your dive, like keeping tabs on your buddy...
 
I have no idea and I dont care - but on average its something between empty and full..
What I do know is that I do as little as possible with my BC and as much as possible with my lungs and weighing..
 
How much air do you keep in your lungs most of the time while diving?

If my answer is "50%" which selection do I choose - 25-50% or 50-75%?

:d

Also do note that it's impossible to expel 100% of the gas volume from your lungs without collapsing them. If you force everything out of your lungs (FEV = forced expiratory volume) there's still about 20-25% of lung volume that has gas in it... referred to as residual volume.
 
https://www.shearwater.com/products/perdix-ai/

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