Careful breathing for buoyancy control

[SlowAndEasy]

Warning: newly OW-certified diver who forgot to ask something really basic of his instructor at the time. Too late to ask her now (I wish I was back in Hawaii), but perhaps it's not too late to ask it here, before I get the chance to do the Peak Buoyancy class later this year.

Basic physics make it obvious why one should never hold one's breath during an ascent. I'm also comfortable with the principles demonstrated when I learned to fin pivot. It makes sense that I'll rise when inhaling deeply and sink when exhaling deeply.

Putting those two basic lessons together, it suggests that effective buoyancy control depends on careful breathing, but too much breathing control can be dangerous in the wrong situations.

Once I started to relax, I realized that I didn't need to breathe deeply while cruising horizontally, let alone keep breathing continuously. I found that I could keep a reservoir of air in my upper lungs and take smaller breaths without exhaling fully.

Is this safe? What are some of the breathing techniques that you use to control buoyancy?

Regards,
Steven

 

[knowone]

Lung control is for stationary and starting and stopping .

Full breathing is for getting there parallel, conscious.

In between is for down and for up.

 

[Aussie Diver 13]

Keeping a "reservoir" as you have called it is fine. In fact, that is one of the techniques of adjusting buoyancy. More air means you rise due to positive buoyancy and vice versa. But as you point out, keep breathing. As long as you keep breathing in and out then your lungs have the opportunity to adjust for changes of pressure as your depth changes.

 

[WetBoy101]

I really love seeing how accurate and still I can be when using my camera. To just hover over or next to your subject without touching anything for stability. Sometimes I don't even care about what I'm shooting, I just enjoy training myself!!

 

[DevonDiver]

Breath control is for fine tuning your buoyancy - minor alterations, so that you can rise or sink a little (to go over a coral head for example) without having to adjust the air in your BCD.

You should still aim to maintain neutral buoyancy at all times using your BCD. Whilst finning flat and level, you breath normally (slow and steady breaths, at your usual lung volume). If you want to rise a little, breath deeper so that your chest expands. Note: you are still breathing in and out as per normal... just a bigger breath each time.

 

[Garrobo]

I would imagine that shallow breathing would cause a build up of carbon dioxide in the lungs. I wouldn't do it.

 

[tbone1004]

ya you want small deep breaths from the bottom of your lungs to prevent CO2 build up.
Like Devondiver said, you want to use your lungs for minor buoyancy changes, but never for full buoyancy control.
I've seen a video of a girl embolise in 3 feet of water and almost die because she took too deep of a breath. Not pretty at all.
BC for rough tuning, to where on an almost empty breath you just barely start to sink then control the rest of it with your lungs.
Proper weighting is also huge here since you don't want a whole lot of air in your bc because it will make all of your depth changes much faster

 

[TSandM]

The important thing about breathing is never to ascend with a closed glottis. What is that? Well, as you are sitting at the computer, take a deep breath, hold it, and push -- this is a closed glottis. It's actually quite powerful, enough to retain sufficient pressure to damage the lung.

Now take a deep breath, and as you hold it, take little tiny breaths in and out. This is an open glottis.

There are two ways to use breath control for buoyancy -- one is to cycle your breathing around a different average volume. In other words, you take a very deep breath, and then cycle some very small breaths around those very full lungs (or, to descend, you do the same thing with empty lungs). The other way is to take a deep breath and maintain it with an open glottis. We do not teach this to open water students, because if you make a mistake, it can truly be fatal.

Notice that the technique of cycling your breath around a different average volume results in smaller tidal volumes (smaller breaths), so it is not something one wants to use for any period of time. It is used to begin an ascent or descent, or to change depth briefly, to go over an obstacle, for example. If you are moving to an extended period at a new depth, buoyancy, if necessary, should be adjusted with the BC. Overuse of breath for this can result in CO2 retention, headaches and nausea, and is also an inefficient way to use your gas.

 

[paddler3d]

It isn't that you want to hold your breath while diving, you never want to close the epiglottis while ascending. When you were doing your CEA or CESA during OW your instructor had you say the 'ahhhhhs' while ascending. This was actually making your keep your epiglottis open.

You absolutely use your lungs to tweak your buoyancy.

More important the breath control for buoyancy is proper weighting, hands down. If you are overweighted, your going to have more air in your BC than your need. As you ascend, and descend for that matter, that extra air is subject to the Boyle's Law, which creates more buoyancy change than is necessary.

When you have your weight correct you'll find that with subtle differences in breathing you can cover a whole range of depths without adding and removing air to your BC.

Once you settle on a depth, you can adjust the air in your BC and then using a relaxed natural breathing style, you'll stay exactly where you want.

As mentioned above, 'shallow breathing' can lead to hypercapnia, or CO2 retention, which can lead to other things.

A way that I've found to really get the feel for what your breathing is doing is to focus and practice hovering is shallow water. Practice hovering at 15 ft, or just off the bottom of the deep end of the pool, or hover mid water in the shallow end of the pool.

Thanks to Boyle's Law, the greatest change in gas volume occurs in the first atmosphere.

As you overbreath or underbreath, you are going to notice the change much more in shallower water. Feedback will be more immediate in shallow water.

 

[Teamcasa]

<snip>Once I started to relax, I realized that I didn't need to breathe deeply while cruising horizontally, let alone keep breathing continuously. I found that I could keep a reservoir of air in my upper lungs and take smaller breaths without exhaling fully.

Is this safe? What are some of the breathing techniques that you use to control buoyancy?

Others have given you good advice but let just reiterate a few points. Breathe normally. Use your breath control to make only minor and temporary adjustments in depth. After making the adjustment in depth, remember to exhale fully several times to reduce CO2 buildup.