Controlling and reducing air consumption

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Nice! Apparently your muscles can learn to do more work with less energy.

In retrospect I should have posted the one where the researcher was regretfully unable to complete his 12 week long study because half the mice died of exertion by week 10. And then there's crazy Russians who seem to believe hypoxia is good for you, but only if you throw hypercapnia in the mix.

The things I learn while waiting for the latest round of patches for the scary intel security horrors to install...
 
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Sorry, but that does not explain the fact that I did a dive trip in September of last year at 240 lb (rather obese as I’m 5’9”) in poor fitness, both physical and cardiovascular. A few flights of steps or moderate exertion would wind me. My RMV on most dives was in the 0.6 range (never below 0.62). After 6 months of training and dieting, I got down to 200 lb and was in very good fitness all around. I dove at the same sites this March under similar conditions and my RMV was consistently 0.4 to 0.46.

I did not pack any more dives in between those trips - the only thing I did was get my butt in shape. I’m even better now as I’ve gotten dowm to 180 lb and in even better physical and cardiovascular fitness and will be back in Grand Cayman in 5 weeks and will enjoy the benefits of my efforts.

So believe what you want, but the “proof is in the pudding” (which I avoid these days :)) and I know that fitness absolutey does make a difference for me - I realize it is not the only factor, but it clearly is one of them for me.
Good for you! Now I need to find out why it makes no difference for me :) BTW, I am at the same 180 pd. With BMI=27.4, I am considered "overweight" yet somehow this does not make me an air hog.
 
but the “proof is in the pudding”
One data point doesn't prove a thing. I've seen many a people drop their SAC just-by-reading-SB. Their classes were deficient in how to relax. I've seen even more people drop their SAC just-by-folding-their-hands. I'm just under 6ft and weigh in at a prodigious 297 pounds and my SAC is just over 0.4 on most dives. I'm the laziest diver you'll probably ever meet.
 
Great... now how about tidal volume? I bet your breath is more than a third more in volume than her's. Worse, the slower you breathe, the less CO2 you'll expel, increasing your angst and probably leading to increased respiration.

There's a theory out there that elevated CO2 levels during exercise actually condition you to be more tolerant of elevated CO2 levels and so "angst and heaving chest" don't happen to those who work out. I read it on the Internet.

My lungs don't fit in the X-ray film. They always have to take the second pix of the bottom half. So yeah, I'll never have SAC so low I'll need a skateboard under it to avoid roid rash down there.
 
One data point doesn't prove a thing. I've seen many a people drop their SAC just-by-reading-SB. Their classes were deficient in how to relax. I've seen even more people drop their SAC just-by-folding-their-hands. I'm just under 6ft and weigh in at a prodigious 297 pounds and my SAC is just over 4 on most dives. I'm the laziest diver you'll probably ever meet.
It's not only this, but in @Joneill case 2 things had happened at once: he lost weight and he became fit. Hence, we do not know which one caused the positive effect.
 
One data point doesn't prove a thing. I've seen many a people drop their SAC just-by-reading-SB. Their classes were deficient in how to relax. I've seen even more people drop their SAC just-by-folding-their-hands. I'm just under 6ft and weigh in at a prodigious 297 pounds and my SAC is just over 4 on most dives. I'm the laziest diver you'll probably ever meet.
I caveated that with "for me". It proves it for my particular case - which is all that I was stating.
 
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It's not only this, but in @Joneill case 2 things had happened at once: he lost weight and he became fit. Hence, we do not know which one caused the positive effect.
I don't need to know - the combination is all that matters (and unless one is sick or starves themselves, better fitness and weight loss normally go hand in hand). Meanwhile, I improved my RMV and also look better, feel better and increased my odds of living a few years longer to get more diving in.
 
I caveated that
and I caveated it even further for those reading this later. Your mind is made up: I can never hope to change that. I do want to drive home the point that technique makes far, far more difference than anything else. No, I'm not saying that other factors can't impact air consumption, but that they have more of a tertiary effect rather than a primary one. For those wanting to understand the techniques I'm referring to, let me list them again:
  • Relax!
  • Move slowly.
  • Avoid currents.
    • Dodge
    • Dip
    • Dive
    • Duck and...
    • Dodge!
  • Stay in the Scuba Position
    • Horizontal
    • In trim
  • Relax!
  • Adjust your depth with your breathing (not your BCD)
  • Frog Kick slowly
  • Make small corrections (not big ones)
  • Make deliberate corrections (be in control)
  • Look more, swim less
    • It's a big ass ocean and you're not going to see it all in one dive
    • Concentrate on finding the small stuff where you're already at!
  • Did I mention "Move Slowly"???
  • Did I mention to "Relax!"???
If you fail to do these, consciously or subconsciously, your SAC will suck no matter how in shape you think you are!
 
and I caveated it even further for those reading this later. Your mind is made up: I can never hope to change that. I do want to drive home the point that technique makes far, far more difference than anything else. No, I'm not saying that other factors can't impact air consumption, but that they have more of a tertiary effect rather than a primary one. For those wanting to understand the techniques I'm referring to, let me list them again:
  • Relax!
  • Move slowly.
  • Avoid currents.
    • Dodge
    • Dip
    • Dive
    • Duck and...
    • Dodge!
  • Stay in the Scuba Position
    • Horizontal
    • In trim
  • Relax!
  • Adjust your depth with your breathing (not your BCD)
  • Frog Kick slowly
  • Make small corrections (not big ones)
  • Make deliberate corrections (be in control)
  • Look more, swim less
    • It's a big ass ocean and you're not going to see it all in one dive
    • Concentrate on finding the small stuff where you're already at!
  • Did I mention "Move Slowly"???
  • Did I mention to "Relax!"???
If you fail to do these, consciously or subconsciously, your SAC will suck no matter how in shape you think you are!
Thanks - I am not discounting those at all and try to dive like that all the time and I have certainly seen my RMV drop the more I have dived, become more relaxed and refined my technique. I'm not sure why folks seem to suggesst I feel this is a zero sum game - I get there are MANY factors and technique is a big one - just not the only one. I'm merely trying ot cover all of my bases.

My personal observaiton was that the biggest drop in progression (for me) that I've seen was when I did the weight loss/fitness thing. Maybe that helped much of the above directly or indirectly by feeling more comfortable, dropping lead, etc. but I did seen an effect. I also found the fitness piece to help alot on a few shore dives with long surface swims through shore break/swells and strong currents. I also did a dive to a deep wreck in strong current where we had to "bomb" down while finning furiously from 60' to 135" to get on the lee side of the wreck. Both of those would have left me winded and sucking air for a while to recover when I was 240 lb/ out of shape - no biggie for me now.
 
I also found the fitness piece to help alot on a few shore dives with long surface swims through shore break/swells and strong currents.
The more you dive, the more you're in shape to dive. I've never seen a skinny whale, and they can outswim either of us with ease. In fact, when I start a surface swim, few can keep up and I'm built like a manatee. Yes, there's a technique to my kick and I'll rest a few minutes before I slip beneath the waves, but I'm not winded. Can I swim against a current? Only if I have to. I prefer to get to the bottom and dodge it instead. I have 4,500 miles in the seat of a canoe, so I can read currents better than most. I just don't get the need to fight Mother, Mother Ocean. I don't get the hubris that anyone thinks they can. She's always gonna win. Always. You have to outwit her, and not take her head on if you want to survive. The odds are never in your favor if you try to power through her. Dive smarter, not harder. Mother, Mother Ocean is a real mother.
 
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