Ways to make tank air last longer...or why can't I stay down as long as my son?

All (5) of my family members were certified in the last couple of months.
We have all had the same approximate number of "post" certifications dives...so we all have about the same experience. We do the same dives, so we basically all have the same dive profile, same depth, same bottom time, etc....its like we are (5) buddies, but we still use air at varying rates.

It cant be physical differences....because....
My 3 sons are/were college athletes, all still working out daily, not an ounce of fat between them ....in other words great physical conditions, yet they use air at very different rates. My oldest must have gills because he can make a tank last forever. My middle son who runs 40-50 miles a week for 10 years uses air at a much faster rate. And ole fat me falls somewhere in between.

Its not age....because I use less than one of my sons (who is less than half my age)

I am looking for ideas to make a tank last longer
1. breathing exercises
I have read that yoga breathing exercises will help with air consumption.

breathe deeper
I heard a boat captain say that breathing deeper would make your tank last longer. I think I was taught "slow-deep" as opposed to "short-shallow-fast"

What is controlled breathing?

Smoking
While none of us are smokers, and I certainly dont advocate smoking, I once heard that smokers use less air. Why?

too much lead Could being overweighted cause you to go thru a tank too fast.


I have read contradicting information on this. I have read that runners use more air, but I also read that athletes use less air. I read that fat people use more and I also have read that they use less. I dont know what to believe.

I am confident that some folks out there have made some type of modification and found it improved air consumption. Please share any ideas.

Thanks for any other ideas!

Some move more efficiently in the water than others.
Stress levels vary between the divers - stress = more air used.

I wrote this a while back:

How fast you use your gas is determined by two things: How much CO2 you are generating per minute, and how efficiently you use the gas you breathe to accomplish gas exchange in the lungs.

To address the second idea first, I'm going to describe a little anatomy. Your respiratory system includes your mouth, larynx, trachea, large bronchi, small bronchioles and then the air sacs where gas exchange actually takes place. Until gas gets into the air sacs, it's just passing through -- it's not delivering any oxygen, or taking away any CO2. If the volume of air you breathe with each breathe is only the volume of your larynx, trachea and bronchi, you're moving a lot of air, but not exchanging any gas. That's why shallow, rapid breathing runs through your tank quickly (and also leaves you feeling short of breath). It's also why slow, deep breaths are routinely recommended by instructors.

Tension and anxiety tend to make people take quick, shallow breaths, which are inefficient. Relaxation tends to allow people to slow their breathing . . . but the funny thing is that slowing your breathing also tends to bring relaxation with it. That's the essence of yoga breathing, or meditation.

Assuming your breathing PATTERN is an efficient one, then you have to look at your CO2 production, which is a result of metabolic activity in cells. You have a certain basal metabolic rate, below which you really can't go. It's actually HIGHER in fitter people than it is in the unfit, so you'd think that getting fit would make your gas consumption worse. But at the same time that your basal metabolic rate increases, the amount of muscle effort you need to accomplish a given amount of work goes DOWN, and that's a much bigger influence. So fitness does pay off.

But efficiency pays off even better. Every motion you make underwater, you pay for with some gas used. Therefore, the less motion, the longer your gas lasts. You can reduce motion by becoming horizontal, so that all your kicking effort succeeds in propelling you forward. If you are tilted at a 45 degree angle to the bottom, each time you kick, you drive yourself upward. To compensate, you have to keep your buoyancy negative, so you will have an equal tendency to sink. At that point, you are expending energy for a net displacement of zero! Very inefficient, and a very common new diver error.

Use your fins, not your hands. Hands are great for swimming on the surface, without fins, because your feet aren't very efficient propellers. But fins are, and that's what you should be using underwater. Flailing wildly with the hands uses a lot of muscle effort and produces very little net propulsion, so people who swim with their hands tend to suck gas.

Master your buoyancy. Although the volume of gas going into your BC or drysuit is relatively small, if you are putting it in and letting it out and putting it back in and letting it back out . . . after a half hour, your BC has breathed a lot of your gas. To master buoyancy, you have to start with proper weighting, because being significantly overweighted will make you unstable in the water column, and result in a lot of yo-yoing that wastes BC gas and ALSO makes you breathe harder. So reducing your weight to the proper amount will, in the long run, make your gas last longer.

And finally, move slower! One of the major strategies of sea life is camouflage, so if you move quickly, you miss many animals you might otherwise find. Unless you have a specific purpose for rapid movement, like spearfishing (and spearfishermen are NEVER going to win any awards for low SAC rates!) slow swimming will result in a much more productive and interesting dive.

Finally, recognize that body size and muscle mass will have a detectable effect on gas consumption. My favorite dive buddy is 6' tall and very strong. He's an absolutely beautiful diver -- quiet, relaxed, balanced and efficient in the water -- but he will never equal my SAC rate, because I'm a little old lady. If you habitually dive with people who are much smaller than you are, then buying bigger tanks may be your best answer.

I am sure that some of the very experienced instructors on this board will offer a lot of valuable information, but I will just mention a few things.

1) Look at your weighting. If a diver is overweighted, he/she will use more air than necessary.

2) Modulate your breathing rhythm. Breathing too fast due to stress, physical exertion, habit, etc., can burn through an air cylinder pretty quickly.

3) Get yourself horizontal in the water and make yourself as trim as possible.

4) Depth matters. Deeper dives use more air. Enough said.

Hope that helps.

"I am confident that some folks out there have made some type of modification and found it improved air consumption. Please share any ideas."

Granny,
I would buy all of your buddy's a long (>5ft) yellow hose for their octos.

The longer hose will allow YOU to sneak up to them and take a few "hits" of air from their tank without ever being detected!!!

and Viola!!!
YOUR air consumption decreases dramatically!!!

Maybe No. 1 son has better buoyancy control and fights the water less than No. 2 son? Maybe No. 2 son not comfortable enough underwater and thus breathing too fast due to nervousness?

Breathing exercise helps. Breath in and out slowly to a cadence count of 1 through 4. Breath in just enough to live and exhale fully so that you don't get CO2 buildup.

Granny Scuba:

It cant be physical differences....because....
My 3 sons are/were college athletes, all still working out daily, not an ounce of fat between them ....in other words great physical conditions, yet they use air at very different rates. My oldest must have gills because he can make a tank last forever. My middle son who runs 40-50 miles a week for 10 years uses air at a much faster rate. And ole fat me falls somewhere in between.

Click to expand...

You will get and have received some excellent advise so far. But let me add a few psi.

Everyone is different and their comfort levels, skills and oxygen requirements differ. I look at it this way, I just dive until one of the team needs to surface and don't worry about who's air is lasting longer.

If the time gap is significant, (like me and my wife's) I just bought a larger tank for me. (I use a HP100, she uses a HP80) and we end our dives with the same amount of air remaining!

Teamcasa:

If the time gap is significant, (like me and my wife's) I just bought a larger tank for me. (I use a HP100, she uses a HP80) and we end our dives with the same amount of air remaining!

Click to expand...

I always try to use 1 size larger than the wife. Swear she has gills I haven't found yet...........

How much are you off? if it is a couple hundred PSI by the end of the dive don't worry about it! I've noticed when I'm consciously thinking about my consumption relative to my buddies I'm toast. If i just relax and do my best then things work out. A couple of my buddies have SAC rates in the .2 to .3 range (unreal really) and I'm in the .6 range, I'm working on it but it isn't the thing to worry about during a dive.

What Lynn mentioned is right on!

Lastly with less than 25 dives your still finding yourself underwater. If at 75 or 100 dives your still having issues than look into a bigger tank.

Have fun diving with your family, it sure sounds great!

For longer dives, I try to stay above my buddy, rather than below.