How Much Air?

[MXGratefulDiver]

Bob, no one is advocating 30 second exhales. We're just saying it can be done, and it is not that hard to do so. I have said several times it is NOT what you should be doing in scuba.

But someone did advocate it fairly early in the conversation ... in fact, he said it was a PADI requirement. He is also listed as a PADI professional, so in this particular forum that might be construed as someone who knows what he's talking about. I think it needs clarification that it is not a recommended practice for safe scuba diving ...

... Bob (Grateful Diver)

 

[boulderjohn]

OK, Bob, to be accurate, someone said a 30 second exhale was a de facto PADI requirement, and he appeared to be advocating it. You indicated that you did not think it could be done. I (and several others) said, yes it can be done, but that does not make it a good idea.So to be accurate, no one among the people who are telling you that it can be done after you said it couldn't are advocating it.

 

[MXGratefulDiver]

OK, Bob, to be accurate, someone said a 30 second exhale was a de facto PADI requirement, and he appeared to be advocating it. You indicated that you did not think it could be done. I (and several others) said, yes it can be done, but that does not make it a good idea.So to be accurate, no one among the people who are telling you that it can be done after you said it couldn't are advocating it.

Actually, I believe I said I couldn't do it, and wouldn't recommend it for my students.

I doubt that I could succeed at a 30-second exhale ... and I'm not going to ask students to do something I can't do. And I seriously doubt there's any such requirement by PADI or any other agency out there. If there is, I'd love to see a reference to the specific part of their standards that say so ...

I'm happy that so many people can. I still don't see that it has any application to scuba diving, and in fact, can be a dangerous practice if it results in shallow water blackout ... which it could ...

... Bob (Grateful Diver)

 

[wetb4igetinthewater]

The 30 second (30 foot really) is a one-off exhalation in the CESA simulation in confined water. It has to be done once, and only once. No one is doing 30 second exhalations time after time.

The student can swim as fast as they want to cover that 30 feet. Since they are swimming along the bottom, they don't get the benefit of expanding air as they would when performing the CESA in open water, starting between 20 and 30 feet and going to the surface.

 

[gfaith]

I'm still a relatively new diver with about 40 dives per date. On most trips, even though I feel pretty relaxed, I go through air faster than most of the other folks on the dive. As per directions, I let the dive master know that I'm at 1500 psi. Looking at my log, I'm finishing dives at times with only 250 psi. All of this makes me uneasy. Any suggestions?

I would highly recommend "The Six Skills and Other Discussions" by Steve Lewis. Chapter Five : The Skill of Breathing has lots of great information on how to breathe when diving and why. Here is quote from page 84, "Think of the breathing in and breathing out as two distinct 'halves' of a complete cycle and make the exhalation phase twice as long as the inhalation".

He recommends doing these pre-dive too and any time you want to release stress. Much more about breathing slowly and deeply in the chapter it has helped my SAC rate and being a more relaxed diver. Works well when your p_ssed at a fellow worker or boss too..

 

[boulderjohn]

I still don't see that it has any application to scuba diving, and in fact, can be a dangerous practice if it results in shallow water blackout ... which it could ...

If only someone had tried to clarify that previously.

More importantly, exhaling while ascending during a CESA is entirely different from exhaling on a normal breath while diving, so this is really not an issue to be considered here.

Again, I emphasize that this is an artificial process designed to overcome the fact that they are required to do the horizontal CESA with no air expansion. Most importantly, I would never, ever, ever advocate this as the way to breathe normally while diving.

But that is a minor quibble--I am just saying YOU can exhale that long--not that you SHOULD exhale that long. I am also not in any way agreeing that exhaling like that should be a part of normal scuba breathing.

So to be accurate, no one among the people who are telling you that it can be done after you said it couldn't are advocating it.

 

[MXGratefulDiver]

If only someone had tried to clarify that previously.

If only somebody was more interested in giving new divers safe and rational diving advice than they were in scoring points in an internet discussion ... PM sent ...

... Bob (Grateful Diver)

 

[TMHeimer]

I may be scoring points as well, but for PADI you must do the CESA on the OW checkout dives too of course. I would suggest going as fast as you could ascending--even from 20 feet--not a good idea. I apologize in not knowing we were just talking about in the pool.

 

[diver_girl_tn]

That can't possibly be right ... a trained opera singer might be able to control their exhale for 30 seconds, but most normal human beings would have difficulty doing so for more than about half that, absent the expanding air on a CESA. And even then, a 30-second exhale would be beyond the ability of most OW students.

.......

I doubt that I could succeed at a 30-second exhale ... and I'm not going to ask students to do something I can't do. And I seriously doubt there's any such requirement by PADI or any other agency out there. If there is, I'd love to see a reference to the specific part of their standards that say so ...

... Bob (Grateful Diver)

As my sister is a professional opera singer and voice instructor, I -- of course -- had to ask her. According to her, she has no problem controlling her exhales for more than 60 seconds, even when moving on the stage, which is usually more breathing intensive than scuba diving. However, it all comes with practice: she practices her breathing pretty much daily and has been singing for ~15 years. Her new(er) students often have a hard time already with 20-25s exhales.

I have been practicing and teaching yoga for years, and can easily control the exhale up to 45s. While I can go up to 60s, I can't keep doing it continuously - let's say for 10-15 minutes or anything like that. And oh boy, when I see a turtle or seahorse - there goes the calm zen breathing out of the window
But respiration muscles, especially diaphragm and exhalation muscles (abs!) can be trained to control the breathing. Which gets me to my favorite topic about being fit to dive.... aerobic conditioning and some abs work will make a huge difference also in diving, in addition to the dives themselves. And I better hit the reply button now before I get too much on my soapbox about the importance of overall physical conditioning ..... once a health nut, always a health nut

 

[MXGratefulDiver]

You people really are missing the point. What you can do on land and what you can ... or should ... do underwater are very different things. Breathing pressurized air changes the physiological equation. And the differences can be risky. Putting yourself underwater while doing so makes those risks potentially dangerous.

Thirty-second breathing cycles in scuba diving can ... almost certainly will ... result in hypercapnia - the buildup of carbon-dioxide in your body. Carbon dioxide buildup introduces a few potential risks ... the most potentially dangerous being that it has an anesthetic effect on a diver's central nervous system. If the concentration of carbon dioxide rises high enough, a diver can lose consciousness. Underwater, loss of consciousness is usually fatal – an unconscious diver generally loses his regulator and drowns.

That's the point. And frankly, this is ... or should be ... covered in basic Open Water training.

Telling a new diver ... someone who's chronically looking for ways to reduce their air consumption ... to do so by slowing their breathing down to 30-second breathing cycles is dangerous advice. Telling them it's a PADI requirement is just outright false information.

Furthermore, slowing your breathing down to that extreme simply will not help you reduce your air consumption ... because you can't sustain it. It will only increase your risks as a diver.

This is the New Diver's forum ... that kind of information just shouldn't be allowed here. It could result in someone who doesn't know any better losing their life.

Now let's address the OP's concerns about air consumption. Yes, slowing down your breathing can help ... but don't overdo it. 10-12 second breathing cycles are plenty of time to make efficient use of your lungs for oxygen to CO2 exchange. But that's not usually why new divers go through their air so much faster than their more experienced counterparts anyway. There are more effective changes you can make ...

• Trim - Think about your position in the water. Staying horizontal to your direction of travel reduces the amount of water you have to move our of your way as you travel. Water's really heavy stuff. The more water you have to move, the harder you have to work. And the harder you work, the more you need to breathe. So "get trim", and move as little water as possible.
• Propulsion - In my Open Water class it was emphasized that we make large kicks ... "using the biggest muscles in your body". Doing so does increase the force of the kick, but it also requires you to move more water ... and you won't get as much return on investment. Use smaller kicks, keeping your legs within the slipstream created by your movement through the water. You won't go as fast, but you'll get from point A to point B with much less use of your air. Besides that, slowing down reduces your overall exertion, and has a huge impact on improving your "miles per gallon".
• Technique - Avoid "swimming" with your hands. It increases drag, throws you out of trim, and does nothing to increase your propulsion ... your "motor" is on your feet. Use it, and keep your hands quiet and relatively close to your body.
• Equipment - A proper fitting BCD helps streamline your body. Keeping gauges and other potentially dangling objects in close to your body reduces drag, as does stowing your snorkel in a pocket or strapping it to your leg when not in use (or better yet, leave it behind unless you're planning to use it at some point). Get a good performance regulator ... cheap regs or one that's poorly adjusted increases your "work of breathing", and that increases the amount of gas you'll go through dramatically. Fins should fit snugly to make an efficient transfer of movement between your leg movement and the movement of your fin.
• Fitness - Can't add much to what the previous poster said ... being reasonably fit makes a huge difference in your air consumption.

If you want to improve your gas consumption, these tips will do far more for you than slowing down your breathing will ... a natural breathing rhythm will occur on its own as you develop your technique and improve the efficiency of your skills and equipment. Don't force your breathing out of some misconception that it'll somehow improve your air consumption ... the risks simply aren't worth the theoretical savings.

... Bob (Grateful Diver)