Air Consumption

[Lamnid]

I got a big problem with air consumtion. I´m always the first one up! I do not have a massive thoracic cavity - I´m just a little girl! But I was looking back over my log book and every dive (which i started on 220 or 200 bar) I have ended with no more than 50 bar. In some cases I´m buddy breathing with the instructor. Now I know what everyone will leap to say: You just need to relax more under the water and breath normally. Well today is my 16th dive and I think i got a pretty good calm going under the water, I certainly don´t feel stressed! I´m at the same depth as everyone else too so no extra air consumption there. I just can´t understand why I´m tearing through my tank each time! Is there anyone else out there with this problem?

 

[Red Sea Shadow]

Several months ago I compiled an article discussing this issue. You can download it in PDF format from http://www.red-sea-shadow.com/downloads/AirConsumption.pdf

 

[MikeFerrara]

First things first...

Learn to plan your dive and gas use so that you don't end the dive having to share air. Better yet, End the dive with enough to get an OOA buddy back too. Regardless of how much air you use, you can't use air you don't have so you had better start planning dives that fit within your air supply...shorter and/or shallower or carry more air.

What are the things that make us breath more? You say you're not stressed. You say your not big. Physical condition? What about work load? When you stop to look at something are you still kicking your feet. Are you kicking your feet to maintain depth? How is your buoyancy control and trim in other words.

Trim...are you oriented head up, head head down or nice and horizontal? If you're not horizontal lots of bad things happen. If you're oriented head up (most common) and you kick, you'll go up as well as forward...so you'll have to be negative in order to move forward only. ok, now you're going forward but you present that large frontal area which means lots of resistance to movement in the water. Now you have to work a lot harder to get anyplace than you would if you were horizontal and streamline like a torpedo. It gets worse though. Remember I said that you'd have to be negative in order to move forward only? Now what if you wish to stop forward movement? You'll sink unless you keep kicking your feet or add air to you BC. Head down trim presents the same problems only in reverse but it's less common. Some divers work pretty hard to go nowhere at all. Does any of that sound like you?

In my experience, some new divers do use a little extra just because they're excited but I haven't found that this is really at the heart of the matter. Most often it's issues of technique.

 

[Kim]

Lamnid - believe me - at 16 dives you're still stressed even though probably a lot less than a few dives ago. Just take it easy and take your time to get things done. Your air consumption will drop on it's own. Worrying about how fast you are breathing your air will just make you breath it faster! Forget it and don't worry now - new/newish divers almost all burn through their tanks. You can't compare your air consumption to an instructors!

 

[MikeFerrara]

Lamnid - believe me - at 16 dives you're still stressed even though probably a lot less than a few dives ago. Just take it easy and take your time to get things done. Your air consumption will drop on it's own. Worrying about how fast you are breathing your air will just make you breath it faster! Forget it and don't worry now - new/newish divers almost all burn through their tanks. You can't compare your air consumption to an instructors!

Nothing happens on it's own. Sometimes divers have to teach themselves important diving techniques and that can take a lot of dives. When they have help they are often pretty good right from dive one.

 

[Kim]

Nothing happens on it's own. Sometimes divers have to teach themselves important diving techniques and that can take a lot of dives. When they have help they are often pretty good right from dive one.

Practice, i.e. more dives, allows people to get better at what they've learned. I don't care who taught them - I've never seen a diver with the same air consumption with their first dives as they have further down the road. Even if they learn perfect technique from the get go they still need practice before it becomes completely natural and second nature. While they are effectively still heavily multi-tasking they'll use more air IMO. With more practice they'll use less. I'm not saying that technique doesn't play a part - that's where the practice comes in....and it's not all learned from an instructor.

 

[MikeFerrara]

Practice, i.e. more dives, allows people to get better at what they've learned.

Ye but getting better at what they haven't learned can take much more practice and that's often the case.

I don't care who taught them - I've never seen a diver with the same air consumption with their first dives as they have further down the road. Even if they learn perfect technique from the get go they still need practice before it becomes completely natural and second nature. While they are effectively still heavily multi-tasking they'll use more air IMO.

Maybe not the same but the difference may be MUCH smaller. ie if the steepest part of the learning curve takes place before certification, so will the largest gains in efficiency. On the other hand, if all that learning is reserved for later, the the gains in efficiency won't come until later.

I wouldn't dream of speaking out so contrary to such common diving dogma if I hadn't had so many students who seemed to be putting air into the tank rather than taking it out during OW training dives.

 

[Kim]

Ye but getting better at what they haven't learned can take much more practice and that's often the case.

Maybe so but let's face it, neither you or I know what the OP has learned or not. At the end of the day there are probably all kinds of technique changes that might help, but I can't, and I doubt if you can either, teach them to people I can't see across the WWW! Personally I think it's reasonable to tell someone with this experience what I said...I also think that what you posted is useful too. Anyway - I sure as heck aren't getting into some kind of discussion/argument over it. For some reason today the whole board seems full of discord but I'm not playing....it makes me stressed and that's bad for my air-consumption!

Lamnid - I do have one question though (well maybe 2!)....I see you're from the UK - who trained you (agency) and where do you normally dive?
(edit: Never mind...I just saw your profile. )

 

[Rick Murchison]

Nothing happens on it's own. Sometimes divers have to teach themselves important diving techniques and that can take a lot of dives. When they have help they are often pretty good right from dive one.

Good point Mike.
We once had (well, we still do have her diving with us, but without the problem) a lady whose air consumption was way higher than what we expected based on her size and diving style and experience. She was at a loss and we were at a loss to tell her why or what to do about it.
Smedley finally figured out that she was using her "normal" workout breathing pattern, the breathing pattern she used on exercise machines at the gym! When Tom told her that Scuba wasn't a workout in the same sense as purposeful aerobic exercise it was like the proverbial light bulb coming on for her and her air consumption dropped by half on the very next dive!
Rick

 

[MikeFerrara]

Maybe so but let's face it, neither you or I know what the OP has learned or not. At the end of the day there are probably all kinds of technique changes that might help, but I can't, and I doubt if you can either, teach them to people I can't see across the WWW!

I agree and if you notice my first post to her asked her a bunch of questions meant to help her evaluate the situation.

While I can't "teach" the techniques over the internet, I can explain the mechanics behind them.

Personally I think it's reasonable to tell someone with this experience what I said...I also think that what you posted is useful too.

There is a good chance that what I posted will be of no use at all. I don't know what's reasonable but the answer you gave is one that's commonly given. While it may be true in many cases, it doesn't help identify a cause or corrective action. Practice is good but better if we know what to practice.

Anyway - I sure as heck aren't getting into some kind of discussion/argument over it. For some reason today the whole board seems full of discord but I'm not playing....it makes me stressed and that's bad for my air-consumption!

Don't get stressed over it. I hope she does well but when this thread ends we'll forget her and find something else to discuss/argue.