Air consumption tips?

[beanojones]

Beano, I respectfully have to correct you. The size of the lungs has NOTHING at all to do with gas consumption. The size of the trachea and major bronchi (volume contained within them) will, but those differences are really quite small.

I dive with one buddy who is almost two and a half times my weight, and significantly taller than I am, whose gas consumption is the same as mine. I dive with another tall, slender cave diving buddy who makes ME turn dives. The ultimate gas consumption you end up with has something to do with size, yes, because more muscle mass means higher basal metabolic rate, and therefore more CO2 production. But efficiency, fitness, and breathing discipline have a lot more to do with it than lung size.

I was using the term 'lung size' as a replacement for tidal volume or more correctly whatever the spirometer measures when the chamber drivers are setting flow rates for inside tender's masks, on air environment chambers which use high o2 masks. Since tenders are all calmly sitting there, (and thus, mostly, fitness is out, except when they take O2 hits), and yet the flow rate can be triple for one tender over another, the drivers tend to use the term big lungs as a catchall for why some people peg the spirometer, and others barely move the needle. You know the terms better than me.

I just know the practical facts of gas supply to tenders and patients meant we were all measured, and the range was much wider than the range of breaths per minute between sedentary and active people, or the breaths per minute of a calm diver to an agitated diver.

Japanese people tend to move significantly less air in a single respiration, as both tenders and as patients. And as divers, to the same ridiculous degree. My common example is for a (nervous, not necessarily fit) Japanese OW student taking over a minute to breathe out the pressure from the hoses after the valve is closed in the air depletion exercise. Americans get a couple of breaths at most, even when they are relaxed fit and concentrating on breathing slowly.

Japanese blood Hawaii raised people used more than Japanese raised in Japan, generally in pretty much the proportion of their body mass. (The Ama pearl divers of course are excepted. They have enormous lung capacity, apparently, though they never ended up in the chamber in Hawaii, so that's all hearsay.)

Since the high O2 from the mask is dangerous in the air of the chamber, getting flow rates right was important, so they measured lots of peoples lung capacity and found pretty wide range in the amount of air moved in a normal breath cycle. Since that is a baseline around which other factors rotate, and it roughly (though not completely) runs with body size...For what it is worth, it actually seems to have a lot more to do with what the person's body size was at the end of puberty more than the present body size. In other words getting fat does not increase the spirometer readings. Where the person was raised (high altitude) does seem to have a lot to do with it, too.

 

[nimoh]

I have been considering yoga for a while to help with breathing. Maybe now it's time to look further into it, but I'll start a new thread

 

[Lizard Leg]

Relatively new to diving, and stopped smoking a few months back when I decided snorkeling /free diving wasn’t enough anymore. I'm an air hog, hands down. I know part of it is being new, part of it is being an ex-smoker (still struggling with it as well) and part of it is being 6', 235 lbs. with one leg. On land, I was told just walking around I use 20% more energy than a two legged person - can't even imagine how that correlates to underwater activities. But that’s neither here nor there. A few months and the lungs should get better after stopping smoking, trying to do cardio to get my fitness level up (just got a new prosthetic Friday to replace one I broke so hopefully I can get back into this) and in general trying to get back in shape and lose weight.

Any suggestions for someone in the ex-smoker, uses more energy than normal, suck a tank dry in 30 minutes at 48’ type diver, other than just cardio and exercise? I keep trying to rent 100's but they always seem to be out.

 

[drrich2]

Any suggestions for someone in the ex-smoker, uses more energy than normal, suck a tank dry in 30 minutes at 48’ type diver, other than just cardio and exercise? I keep trying to rent 100's but they always seem to be out.

This may not be practical due to weight issues getting tanks & gear into & out of the water, but side mount diving would give you the option to take two 'off the shelf' rental 80 cf aluminum tanks (each with its own regulator & SPG) on your dive, and breath 2/3'rds of the gas from each. If you're somewhere that has plenty of 80 cf tanks, could be useful.

Richard.

 

[Lizard Leg]

Boat diving not an issue I guess, but shore diving would give me fits with that much weight! I already have issues with being way over the weight limit for the foot. I've never done a sidemout tank... might have to talk to my instructor come Oct. when we do the AOW course.

Thanks!

 

[DukeAMO]

Helpful thread, thanks.

So, here's a little trick to avoid using your hands when you should be using your fins -- I take a small dive light and hold it in both hands, and point it at what I'm looking at. The dive light dangling off of my wrist reminds me every time I've started using my hands for something else. Other people I know put their computer on their right wrist (so it's not on the same hand as the BCD deflator), and grab their right wrist with the left hand. Anything to break that bad habit!

In Cozumel, they have some pretty significant currents. They also have some very interesting and challenging (narrow) swim-throughs, some with current in them. I found that my air consumption was the worst in Cozumel, and I think it's partially because I was working hard to avoid touching the reef on 3 sides. The DM was just gliding along, barely finning. Practice, right?

 

[farsidefan1]

Good to hear from you and welcome. Sometime after about 30 dives you will "magically" become more efficient in you air consumption. I got some help in getting my trim and weight properly setup and instantly went from a SAC tate of ,7 to .5. I added a wetsuit shirt and now since I'm not shivering at end of multiple dives on multiple days I frequently am in the .4 range with a low of .38. I'm 5' 11" and weigh in at 240. Just dive and adjust your trim so you are streamlined and not over (or under) weighted. I have no trouble getting an hour + out of an al80.