Bigger lungs, greater air consumption

[DeepSeaExplorer]

Obviously, there are some things you can do to reduce consumption. However, given an equal number of breaths per minute, the larger lungs will require more volume.

All other things being equal, a 250lb person is going to consume more air than someone who weighs 150lbs. That's why women generally have a lower SAC than men.

 

[DENNISDIVES]

Good physical condtion and good cardio conditon will extend your dive time. You need, on a regluar bases, a good cardio work out, running, bike riding, brisk walking or swimming will help.

 

[jeter]

But.... for the sake of the argument.... doesn't it make sense that bigger lungs equals bigger volume of air per breath and hence faster consumption? Don't worry, I won't cling to this as an excuse for being an air hog.

Larger lungs can actually actually help air consumtpion. I use my lungs in place of my BCD for 90% of my diving, leaving the BCD almost completely empty unless I am on the surface. I have contol over my position in the water coulumn because my lung large volume is not effected by change in depth, just my breathing. I breath of the top of my lungs when I want to go up, breath of the bottom of my lungs when I want to go down and the middle the rest of the time.

This help save air two ways.
1) No air is going into and out of My BCD
2) My deflated BCD is more stream lined

Remember, you do not have to breath as fast as those small lunged girls.

My 2 cents,
Jay

 

[djb_1965]

As stated, cardio-vascular condition plays the major role. The better shape the body the more you get out of each breath. When I started diving, I too was an air hog. My wife would use half of what I did. Once I learned like others have stated here, slow, bouyancy, weighting....now I make her mad cause I use less than her.

 

[ian@1904]

Try some yoga breathing exercises

Just accept you are a novice diver, for the moment. Take a bigger cylinder.

I started of using 15ltr cylinders and could make them last about 40mins at 20m. Today I have done two dives for 40 mins on the same cylinder. The more diving you do the more relaxed and better your gas consumption should become.

Gas consumption is not a competition. One frind of mine has a SAC of about 8 Litres per minutes, I am about 12LPM. Another friend has 25LPM after hundreds of dives. He uses twins 12s for 35m dives and twin 15 for trimix.

 

[scubafanatic]

I have twenty dives under my belt now and am focusing on improving my air consumption. I am a fit 37 yr old male but can't seem to get more than 35 minutes on a max 60 fsw (warm, slight current) dive with an AL80 tank, while others are getting 45 minutes.

I have worked with divemasters on trimming my kit, adjusting weight and trying different fins. One suggestion I heard was that I am a big, athletic guy (6'2", 225lbs) and presumably have a big lung capacity, so am simply breathing more air from my tank per breath than others. This makes sense that if I take a deep breath I could be taking it a lot more air than, say, my wife (5'5", 120lbs). But then I see other big dudes getting more bottom time than me.

What gives? Am I destined to be an air hog? Should I be using a bigger steel tank to account for higher air volume needs?

Thanks for any feedback.

...well, to become 'equal' to your dive buddies, who are 'beating' you in a 45/35 ratio, you need need approx 29% more 'gas', so if you, say, used an AL 100/steel 100, that would give you pretty much the same bottom time as the rest of the group, if they're all on AL80's.
Your wife has half the body mass you do, so you can't expect to compete with her, but where possible at least try to dive 'the next size up' tank from whatever it is she's diving to even out your dive times.

Karl

 

[donkey]

I'm a fairly new diver, and I've noticed that practice makes an unbelievable difference. A couple of years ago I went on a week-long dive trip in warm water. On the first dive I was able to spend about 25mins at 30'. (No laughing please ) By the end of the trip, I was up to 60mins at 40'. My gear configuration didn't change (though I could probably have dropped a couple of pounds from my belt), it was all about being more relaxed.

Now, of course, it's been far too long since that trip and my air consumption is high again.

 

[ryanpublic]

This thread inspired me to analyze my SAC Rate. So I looked at my logs and it looks like two years ago it took about 50 minutes to kill an 80, Last year 70, and this year 80. So my SAC rate has improved quite a bit in two years and about 210 dives. I'm 6'0" and 230lb.

 

[chgodvr]

It usually takes more than 20 dives to become relaxed and comfortable in the water. Watch how the other, more experienced divers in your group breathe. Also watch how they move through the water. Try to emulate them, but sort through the differing styles to find things that you are comfortable with. One of the most interesting articles I've ever read about air comsumption underwaterstated you need to rethink the way you breathe when underwater. On the surface, we all inhale and then immediately exhale, pausing after the exhale before inhaling again. Underwater, you need to move the pause to after the inhale. (Before everyone screams about breathholding, watch how divers breathe, how we breathe is the most important part of bouyancy control, we just call it airway control). Get out and dive, even if it is only in a swimming pool. Work on relaxing, and airway control. But most of all, just have fun with the sport!!

 

[dumpsterDiver]

My SAC is around 0.8 for most active dives and I have been diving for a long time. If you are big and strong and want to stay down as long as most smaller people, then get a few bigger tanks and enjoy diving. Stop trying to "improve" your air consumption. Simple as that. It isn't a contest.

If you use large steel tanks, you will probably be able to reach the no-deco limit for nitrox at most depths without changing your gas consumption.

Of course all the advice about breathing correctly and trim etc is very useful, but your goal should be to move throuh the water efficiently and in a relaxed manner, which is not necessarily equivalent to using less air than the "other guy".

I often do dives with 125 cu-ft steel tanks and have 1/3 of the air left over very frequently. I don't have to worry about my breathing rate, because it really doesn't matter.

This weekend I went to the shop at 6:30 am and the compressor was down and I got only 2000 psi in my tanks from their banks. I had to "try" to conserve air to get two dives from the one tank and it honestly reduced my enjoyment of the dive. Trying to conserve air just serves to be one more source of stress during the dive. Luckily I have larger tanks!