No breathing instruction?

[barry1961]

I have noticed there is not much breathing instruction besides "breathe normally". This seems like an important enough topic that it would have a chapter dedicated to it. Some of the most common problems I hear or notice are from improper breathing and the divers always say no one told about breathing in class. Beginers end up breathing rapidly with full lungs and feel like they can't get enough air.

Just a very, very rough and rounded explanation I give is.

CO2 build up makes you want to breath and gag, not lack of oxygen
1 liter equals 2 lb of lead

6 liters of air total

1 liter of air stays in lungs always
1 liter more stays in unless you exhale hard
1 liter flows in and out while doing mild activity, 1/2 liter at rest
3 extra liters if you inhale all the way

So normally you get 33% fresh air to flush out the CO2
If you inhale all the way and breath "normal" you get 16% fresh air to flush out CO2
If you inhale all the way and short breath it drops to 8%? fresh air? Gagging/smothering.
If you inhale all the way it adds 6 lb of lead
If you exhale all the way and breath normal you get 50% fresh air.
If you exhale all the way and breath normal it drops 8 lb of lead.
You can see quickly that the key is to exhale which is hard for beginning divers to do.

I am 6', 280 lb and don't need any lead with a steel tank, 5/3 suit, hood and TransPac, no plate. With a 100 cft tank it is hard to come up with less than 1000 psi without going into deco. Before I learned to exhale I was using 10 lb of lead and sucking down a 120 cft tank way before deco. Now I am thinking about going to 80 cft tanks.

I know total and tidal air volume is different for everyone but the basic exhale rule is the same. It seems someone should do a good explanation and put it in a course.

Barry Payne

 

[lowviz]

Buoyancy and trim.

Trim is being able to hold a horizontal position in the water column without motion or conscious effort. This is mostly physics. You get your gear sorted out and weights placed properly and it happens.

Breathing is tied to buoyancy. If you breathe 'all over the place', you will have constant buoyancy issues. I know this for a fact, it caused me great difficulties up until just lately.

http://viewzone2.com/breathing.html

http://www.scubaboard.com/forums/basic-scuba-discussions/261380-correct-breathing-pattern.html

 

[TSandM]

You're right! New divers really need to exhale, but even if you explain that, it's almost impossible to get them to do it. I don't think presenting the numbers would be any more compelling than simply having the mechanics explained, but neither is going to override the anxiety that makes new divers keep their lungs full.

 

[MauiScubaSteve]

IMHO, only those non divers who are pretty much deathly afraid of being underwater can not apply this simple "mantra"...

Got to get the bad air out to get the good air in.

If it were almost impossible to get new divers to exhale, certifying new divers would be almost impossible, and the annual new diver certifications numbers seem to rebut that opinion.

 

[XS-NRG]

I was looking at the above posted links to other threads and then responded to one that was 3 years old by accident but I'll repost it here too:

I doubt the typical basic scuba diver even understands how impressive a breathing rate of less than 4 breaths per minute is, but I just have to say - very impressive. I know a petite instructor named Cindy that nears 4 bpm when relaxed and I thought she was suffering brain damage

I just tried this and with absolutely no effort I was already at 4 Breaths Per Minute. The easiest way to think about this relates to meditation and the metaphor of making your bed. Everyone knows how to make their bed; throw the sheet in the air and it gathers air and then slowly falls back down. Think of your breathing as the same. The inhale is the throw in the air, as the bed sheet reaches the top of its peak slow your inhaling (but keep imaging the bed sheet going up just a bit higher and naturally flowing), your inhale will stop/pause (but more so it will just become severely reduced), then as the bed sheet falls you are exhaling very slowly and continuously but much slower than the inhale. Once the sheet hits the bed (imagine watching all the final little pockets of air subside) you think your lungs are empty you will stop/pause (again it will just be a very reduced exhale) then repeat. You don't actually ever stop at the apex of the breath whether inhaling or exhaling.

Your breath is just a giant waveform. Slow, continuous and flows at an even rate. The frequency is long and curvy, there are no sharp changes to the parabolic curve, although the exhale is considerably longer.

Looking at this image you will see that the top sinewave is natural (the way your breath and the bed sheet would be), the second sinewave is what it would look like if you actually stopped and paused at the apex of each breath (both inhale and exhale). Clearly the top one is the way you would want to breathe, just remember that the apex is severely reduced but not fully stopped.

Doing this exercise my heart rate is about 40-50 BPM. Using a different technique I learned in martial arts I can get down to 30-40 BPM heart rate but I wouldn't recommend that while diving

 

[Rhone Man]

I just tried this and with absolutely no effort I was already at 4 Breaths Per Minute.

Just to clarify, was that above water at rest, underwater whilst swimming, or some other variant?

 

[XS-NRG]

Just to clarify, was that above water at rest, underwater whilst swimming, or some other variant?

That was sitting here at my computer reading the posts/threads :cool2:

I did do some deeper breathing in much the same way underwater on my last couple dives but I have no idea how many full cycles per minute it was. I do recall the exhale being very long, but I'm sure the 8 degree Celsius water would have increased that number

 

[barry1961]

I think one of the keys is to exhale more when diving. The extra helps offset the extra volume in the regulator, not much, and reduces CO2 which helps you relax. If you take a full breath of air, 3 extra liters, and exhale the full amount every breath you will empty a tank quick and require 6-8 lb of extra lead. If you normally breath 1 liter every 10 seconds inhaling 3 extra liters will not change your breath rate to every 30 seconds. Taking a deep breath sucks air, adds lead and usually increases CO2.

Exhaling the extra 1 liter and inhaling a "normal" 1 liter will reduce the CO2% in your lungs whichs relaxes and extend air suppy. Inhaling to max lung capacity every breath does not work well above or below the surface. Breathing normally through your mouth takes practice, which is better to do above water or in a practice pool.

Barry Payne

 

[MauiScubaSteve]

For the record, instructor Cindy from my 3 years ago post breathed 4-ish breaths per minute "gently guiding" Shark's Cove way back early in this century. For all I know she could be 4 breaths per minute teaching/guiding 4 OW students at Shark's Cove now.

Breathing in normally is best, except when your buoyancy needs you to not breath in normally.

Exhaling is key; the best exhale is a full exhale, except when your buoyancy needs you not to fully exhale.

I'm usually having more than gentle fun, so I think ~2 sec inhales w/ ~5 sec exhales, or something like 9 breaths per minute, would be peachy. 41 beats per minute on my most recent visit to the Doc, as long as I get enough air.

 

[MXGratefulDiver]

I not only teach breathing techniques, I demonstrate it and have the students practice it during class. The presentation goes something along these lines ...

"For most of us, scuba diving is the first time in our lives that we actually have to think about breathing. How we breathe affects two of the most difficult things for a new diver to learn ... good buoyancy control and good air consumption. Doing it wrong means that you will build up carbon dioxide in your body, which will cause you to want to breathe harder. Doing it properly means that you will feel more relaxed and comfortable. So I'm going to show you how you should breathe underwater, then I want you to try it."

The cycle I demonstrate takes about three seconds on the inhale, about a one-second pause after the inhale, and about six seconds on the exhale .. a 10-second cycle altogether.

I also discuss breathing when it comes to weighting, explaining that one reason why new divers chronically carry too much lead is because they have trouble descending. I explain it this way ...

"A lot of times if you're having trouble descending it's because you're not breathing out all the way. Think of your lungs like another, internal BCD. If you keep air in your BCD it prevents you from sinking, right? Well, keeping air in your lungs does the same thing. So on the descent, as soon as you start letting air out of your BCD take a big deep breath and hold it. Once you sink to about eye level, start breathing out as you finish emptying your BCD. When you're done breathing out, breathe out some more. By the time you've emptied your lungs completely, you'll be a few feet underwater ... where pressure is your friend. Now you can breathe in again without sending yourself back to the surface."

I also talk about how to use your lungs to control your buoyancy while on the dive ...

"The secret to good buoyancy control is staying on top of it ... be proactive rather than reactive. You do this with your breathing. Think about your lungs like a "fine-tune" BCD. When you want to make buoyancy changes, use your lungs first ... because you can react much more quickly with your lungs than with your BCD. If you find yourself starting to ascend when you don't want to, breathe out first ... as you're reaching for that inflator hose. Of course, once you breathe out you'll need to breathe in again. So now you can let a little air out of your BCD as you're breathing in. The reverse applies if you find yourself sinking when you don't want to ... breathe in to stop yourself, then add a little air to the BCd as you have to breathe out to keep you there."

Overall, I find that discussing techniques in conceptual terms is easier for most people to understand and remember than using math ...

... Bob (Grateful Diver)