Would a large lung capacity contribute to hogging air?

[serambin]

First, you do not get anything for nothing. By that I mean, you must resupply your body's O2 consumption with . . . O2. So the real question is maximising your rate of O2 / CO2 exchange.

Lung capacity is meaningless. A slow steady respiration rate gives your lungs time to exchange the new O2 for the CO2 from your blood, this is the key. Try a pool dive staying fairly stationary and using a counted 4 second inhale and 4 second exhale rate. Count like this - 1000 and 1, 1000 and 2, etc.

Check your SAC rate and use this as a base line for future checks. It is worth burning a tank on.

Watching my diving partners, I've come to belive that the 'steadiness' of breathing is a key factor to low SAC rates. More important than your size or to some degree fitness. My SAC rate is almost always the lowest or at least right around he lowest in any group I dive with. I think much of this is due to experience and to steady breathing rates.

Stan

 

[finley]

you only use 16% of the o2 taken in on each breath....if your body is demanding more than that due to increased activity, extreme conditions (hot or cold..panic etc) then you have to breathe more often. THe depth of the breath doesnt really increase o2 exchange but can certainly help in the panic department. Fitness level comes in with how easily and efficiently the 02 exchange can take place ( and the cardiac demands of hauling yourself around).

 

[CameronMartz]

I am extremely impressed by the number of "Myth Busters" out there when I have frequently felt like I am fighting windmills with the lung volume vs. gas consumption issue. Gas consumption is linked to metabolism, not lung volume. People with big lungs will just take fewer breaths in one minute than someone with small lungs of the same metabolism. You cannot overbreathe your metabolism very long- this is textbook hyperventilating, and again, it can happen just as easily to someone with small lungs as with big lungs.

If your breathing rate is high, that means that your metabolism is high. This could be due to body size, but in new divers, it usually includes a lot of unnecessary movement, buoyancy and trim corrections, etc., that get better with experience.

While I agree with the advice to "just dive," I also think that divers can take several conscious steps to reduce their gas consumption without taking the fun out of diving. I have an article at http://www.divefitness.com/html/articles.html titled "Breathing Heavy: How to reduce your gas consumption" with some other ideas to think about.

Cameron

 

[Zeeman]

Don't close your throat and hold your breathe. Instead, with an open throat, use your diaphragm to pause before you exhale. This will provide additional time for more gas exchange, and make your breathing more efficient.

Why thank you, that is a very helpful tip Will try it on my next dive

Z...

 

[Zeeman]

http://www.divefitness.com/html/articles.html

Cameron

That too - never seen that before. Thanks for sharing

Z...

 

[The Kraken]

I don't think that aspects of the physical body size should be factored into "hogging" air.

A diver has no control over the size of lungs, etc.

Those things that contribute to "hogging" air, in my opinion, are those which the diver can correct . . . weighting, techinque, relaxation, etc.

the K

 

[Puffer Fish]

I am extremely impressed by the number of "Myth Busters" out there when I have frequently felt like I am fighting windmills with the lung volume vs. gas consumption issue. Gas consumption is linked to metabolism, not lung volume. People with big lungs will just take fewer breaths in one minute than someone with small lungs of the same metabolism. You cannot overbreathe your metabolism very long- this is textbook hyperventilating, and again, it can happen just as easily to someone with small lungs as with big lungs.

If your breathing rate is high, that means that your metabolism is high. This could be due to body size, but in new divers, it usually includes a lot of unnecessary movement, buoyancy and trim corrections, etc., that get better with experience.

While I agree with the advice to "just dive," I also think that divers can take several conscious steps to reduce their gas consumption without taking the fun out of diving. I have an article at http://www.divefitness.com/html/articles.html titled "Breathing Heavy: How to reduce your gas consumption" with some other ideas to think about.

Cameron

This thread, for the most part, has actually stayed on topic and there has been some excellent post - I commend everyone.

There are a couple of other issues that can effect breathing rate, that tend to get ignored:

1. The regulator you are using and how it is adjusted. As I have recently found out, it is possible to have a very high end reg, that is adjusted incorrectly. It takes energy to breath, and in some cases, it can take a lot. Unfortunately, this effects the big lung person more, because of the rate of inhaling is faster.

2. All breathing system have slightly higher dead air space, and in some people, this can increase your breathing rate. That small amount of CO2 can and does effect people differently. Oddly, this is more an issue with the physically fit, because they usually have a more sensitive CO2 sensing system. An easy test of this is to do the snorkle test. Relax, breath normally and count breaths, then breath through a snorkle and recount. (note: Usually better to have someone else do the counting, and be careful to relax and breath normally, and you have to wait after switching to count).

As has been pointed out, different size people will naturally use different amounts of air. A 200 lb guy, all things equal, has no chance of matching a 120 woman. But there is also the issue of fast twitch versus slow twitch muscle and how they use O2. Being strong is actually a bad thing here, if the strenght is from fast twitch muscle. It can use air, really, really fast. As women tend to have less of this, they also tend to be far more even in their air usage.

I know divers, who have great sac rates, but are also of the minimal effect diving concept. They decide where to go, what to see, based completely on the energy it will take. Makes great use of air, but sort of takes some of the fun out of diving (for me anyway)

One of the great ways to tell where you personally fit in this, is to just get a tank of air and test your resting and working SAC rate, and compare to your dive buddy. Easy to do at home and somewhat fun.

 

[BarryNL]

What surprised me a bit was that I seemed to burn through air really quickly during my pool sessions. (even the last few where I felt really at ease and practiced my breathing)

My thoughts are that if you take in significantly more air with each breath and you only actually process a small amount of the oxygen your lungs take in, would having a larger lung capacity ad to the problem of air hogging compared to another individual with a lower lung capacity?

You need to remember that breathing actually serves two purposes in SCUBA. Firstly, the obvious supply of oxygen, but secondly (which never seems to get talked about much) its your fine control of your buoyancy. Most likely as a new diver you are breathing more air trying to keep your buoyancy under control than you are using for your oxygen requirements.

The good news is that this will drop drastically with experience! Once you have about 50 dives under your belt buoyancy control will be second nature and you will probably be amazed how much your air consumption drops.

 

[The Kraken]

New divers are more prone to be constantly inflating and deflating their B/C's.

This action adds, rather significantly I might add, to the amount of air used during a dive. Goes along with the buoyancy thing.

the K

 

[Buoyant1]

Case in point.. I had a brand new set of regs, and they seemed to breath rather easy and almost "over supply" air. Two dives I did with them were very dis-heartening as I thought I was getting over the air-hog problems, and I spent one dive at 23 minutes!

I did a local dive with one of the guys from my LDS and showed him, at depth no less, how it was over supplying, he had me bring the regs in, did a quick service and my next dives were great! The record dives were the dives I mentioned before.

Lot's of factors involved with it, but I think the more you dive the better it gets!

This thread, for the most part, has actually stayed on topic and there has been some excellent post - I commend everyone.

There are a couple of other issues that can effect breathing rate, that tend to get ignored:

1. The regulator you are using and how it is adjusted. As I have recently found out, it is possible to have a very high end reg, that is adjusted incorrectly. It takes energy to breath, and in some cases, it can take a lot. Unfortunately, this effects the big lung person more, because of the rate of inhaling is faster.

Snip....

.