Breathing styles?

[MaxTorque]

Whilst diving, I've always tired to breath slowly and relatively deeply, perhaps 4 to 5 dec breath in, and 6 to 7 sec breath out, using my diaphram as much as possible to get the best air exchange and CO2 flushing. My SAC tends to sit between 11 and 13 l/min depending on circumstance.

However, watching some vids on You-tube, and i notice that some divers are doing a relatively short and sharp exhale? Ok, they are doing this when demonstrating something in neutral buoyancy, so i guess at this point they are trying to stay at a stable depth and not to rise and fall as they breath, but is there any other advantage to this technique?

For example,. here:

 

[Wibble]

Steve Martin's exceedingly experienced so doing a demo like that would not faze him in the slightest.

You need to breathe to suit you. Obviously he, who's very fit and healthy, would probably consume a lot less gas than most others. Hence he effectively breath holds. As it will affect his buoyancy and as an experienced sidemount cave diver, he'd probably tend to do the breathing cycle as an exhale then inhale to keep the buoyancy bang on.

Nice demo. We all should be able to do that and aim for those standards. Lots of practice required though.

 

[Wibble]

Steve Martin has a paid-for video series which is the same as a crappy AOW eLernin book replacement. Far better value for money IMHO. Covers from beginning to advanced (as in proper advanced) and various styles.

Thoroughly recommended

 

[johndiver999]

When a diver is essentially resting or static and is primarily focused on neutral buoyancy, it may be advantageous to breathe shallowly. Large variations in lung volume are going to affect lift.

If your intent is to breathe efficiently and presumably support some degree of activity, then the breathing pattern described by the OP is probably more advantageous.

My advice is generally deeper inhales and slightly more degree of exhalation than you would normally use on land, but the manipulation of the breathing pattern needs to be subtle and not drastic or it will feel unnatural, stressful and will make you nervous and this will make things worse, rather than better. Don't try too hard to conserve air, it just isn't worth it.

Concentrating on being relaxed and calm and limiting unnecessary activity are generally far more productive than trying to over modulate your breathing pattern.

 

[RainPilot]

All the OW books make a big point of "Don't breathe shallow!" and fail to adequately explain why. I then end up having to "fix" folks who adopt a high tidal volume breathing pattern, which is hell on relaxed buoyancy control.

The intent of the "avoid shallow breathing" warning is to try prevent folks from doing VERY shallow breaths, usually in an attempt to conserve gas / reduce SAC. This leads to retained CO2, usually, which then gets you breathing much faster once your body takes over from too much CO2. Oxygen is not a problem, the PO2 at depth means that your rate of breathing is WAY more about CO2 exchange than getting enough O2. My advice is to try a 2 sec in, 3-4 second out, relaxed shallower breathing pattern. If you are getting enough CO2 exchange, you'll be able to maintain it indefinitely. if not, you'll know pretty quickly and then can adapt accordingly.

The aim is to get the shallowest breathing that can adequately get rid of CO2, this will also depend on rate of CO2 production so higher workload will need deeper breathing.

 

[johndiver999]

All the OW books make a big point of "Don't breathe shallow!" and fail to adequately explain why. I then end up having to "fix" folks who adopt a high tidal volume breathing pattern, which is hell on relaxed buoyancy control.

The intent of the "avoid shallow breathing" warning is to try prevent folks from doing VERY shallow breaths, usually in an attempt to conserve gas / reduce SAC. This leads to retained CO2, usually, which then gets you breathing much faster once your body takes over from too much CO2. Oxygen is not a problem, the PO2 at depth means that your rate of breathing is WAY more about CO2 exchange than getting enough O2. My advice is to try a 2 sec in, 3-4 second out, relaxed shallower breathing pattern. If you are getting enough CO2 exchange, you'll be able to maintain it indefinitely. if not, you'll know pretty quickly and then can adapt accordingly.

The aim is to get the shallowest breathing that can adequately get rid of CO2, this will also depend on rate of CO2 production so higher workload will need deeper breathing.

I agree that elimination of carbon dioxide is the challenge. However, doesn't shallow breathing reduce CO2 elimination by pushing a higher percentage of air volume through the dead air space of the respiratory tract?

 

[RainPilot]

I agree that elimination of carbon dioxide is the challenge. However, doesn't shallow breathing reduce CO2 elimination by pushing a higher percentage of air volume through the dead air space of the respiratory tract?

The shallower the breathing the lower the CO2 exchange, correct. The ideal is to have the ideal balance between overly shallow (great buoyancy, terrible CO2) and very high tidal breathing (opposite). I find that more students over breathe than under breathe, it is almost always an overreaction to the warnings they got on their OW course. Everyone's mileage may vary, but most folks start to breathe shallower as they become more experienced, its part of the phenomena of SAC rate coming down as you gain experience, along with more efficient finning etc and more comfort in the water.

 

[johndiver999]

The shallower the breathing the lower the CO2 exchange, correct. The ideal is to have the ideal balance between overly shallow (great buoyancy, terrible CO2) and very high tidal breathing (opposite). I find that more students over breathe than under breathe, it is almost always an overreaction to the warnings they got on their OW course. Everyone's mileage may vary, but most folks start to breathe shallower as they become more experienced, its part of the phenomena of SAC rate coming down as you gain experience, along with more efficient finning etc and more comfort in the water.

Ok, thanks. It sounds like we agree on most of the concepts, but arrive at a different conclusion.

I am generally far more concerned about effectively flushing co2 than variations in buoyancy. On deeper dives and as activity level increases, the more complete exhalation effort has helped reduce or eliminate co2 headaches for me.

 

[scubadada]

Whilst diving, I've always tired to breath slowly and relatively deeply, perhaps 4 to 5 dec breath in, and 6 to 7 sec breath out, using my diaphram as much as possible to get the best air exchange and CO2 flushing. My SAC tends to sit between 11 and 13 l/min depending on circumstance...

That's pretty good gas consumption, have you voted in the poll? Average Gas Consumption

 

[tbone1004]

@Wibble being in great shape is not an indicator of good SAC rates and quite often can be the opposite. Higher muscle mass means a higher generation of CO2 in the body which needs to be expelled via breathing, so someone with less muscle mass is generally going to have to breathe less. That isn't a rule obviously but some of the best SAC rates I have seen were from people that when you look at them you'd be scratching your head, and the opposite when you look at some of the students we have sent off to be Navy SEALs who have comparatively high SAC rates.

to @MaxTorque a lot of the breathing patterns are going to be based on what your brain is comfortable with. For example, competitive swimmers or former musicians may have a sharp inhale and a long exhale as that mimics the rhythmic breathing that is trained in swimming and playing wind instruments. Someone who practices yoga/meditation may have a long inhale followed by a long exhale, etc.
Your current SAC rate of 11-13lpm or 0.4-0.45cfm is definitely on the low side and you may be bumping up against the bottom limit of SAC rate for your body.