holding breath on scuba

[bober99]

They teach you never to hold your breath on scuba but I've been wanting to get closer to fish and was wondering if the following would be safe:
-holding breath on exhale: I can exhale all my air and still hold my breath for about 30 seconds before needing to inhale again
-holding breath on descent: I see some fish below me and hold my breath to get closer to them but breath out before heading back up

The only reason I see for not holding your breath is that on the way up the air expands and can cause an embolism. So one should be safe holding your breath on your way down or on empty lungs right?

 

[ERP]

I doubt your lungs are ever completly empty, so there is always some danger and I personally wouldn't condone getting used to holding your breath even on a decent.

You are much safer if you never hold your breath underwater.

Having said that, you are correct the danger with holding your breath is an embolism which requires that you both close your glotis (hold your breath) and decrease the surrounding pressure (ascend).

Note it is actually possible to stop breathing without closing you glotis.

 

[Ann Marie]

Good question. When I dive (as long as I am not ascending) I take in a breath and hold it for a moment. I figure that gives my lungs optimum time to use the oxygen in the breath to their full advantage. I first read about doing that in an article in a dive magazine. I find that when I do this and am conscious about my breathing my bottom time is much better.

**I edited my reply to try and make my response a little more clear regarding the breathing technique I employ.

 

[Boogie711]

Ann Marie - that's called skip breathing, and it's dangerous. It's a good way to load up on CO2 which you do not want. I would urge you to re-think that practice.

 

[cornfed]

Ann Marie - that's called skip breathing, and it's dangerous. It's a good way to load up on CO2 which you do not want. I would urge you to re-think that practice.

I thought skip breathing was when you inhaled twice before exhaling.

 

[pilot fish]

Ann Marie - that's called skip breathing, and it's dangerous. It's a good way to load up on CO2 which you do not want. I would urge you to re-think that practice.

yes, I've heard that but I thought it was that you built up carbon dioxide?

I think the trick to holding your breath, NEVER WHILE ASCENDING, is to not close your throat.

 

[onfloat]

yes, I've heard that but I thought it was that you built up carbon dioxide?

???? CO2 is carbon dioxide.

 

[jonnythan]

pilot fish, yes that's the reason you don't hold your breath. Once you inhale, you want to exhale fairly quickly to blow off excess CO2. Skip breathing retains CO2 and is pretty bad.

 

[pilot fish]

???? CO2 is carbon dioxide.

duh, one me. I ignored the C and just saw 02

 

[MXGratefulDiver]

Ann Marie - that's called skip breathing, and it's dangerous. It's a good way to load up on CO2 which you do not want. I would urge you to re-think that practice.

Not completely true ... actually what's described is a legitimate breathing technique, although a 3 second pause is a bit excessive.

Skip breathing and pausing between inhale and exhale are very different things.

The first implies that you are actually holding your breath, closing the glotis, for several seconds. This will, in fact, lead to CO2 buildup, as you say.

However, pausing for a second or so between inhale and exhale allows a more effective exchange of inhaled air with the CO2 that your lungs want to expel. It just gives the alveoli in your lungs a bit more of a chance to do what they're designed to do. For safety sake you do want to keep your glotis open (like you do with the "aaaahhhh" they teach you in OW).

FWIW - pausing your breathing for brief periods isn't inherently dangerous in and of itself ... we do it when doing regulator handoffs for OOA drills to better maintain buoyancy. What IS dangerous is doing it with glotis closed ... for the reasons they teach in OW ... especially when you don't have the requisite skills to hold your buoyancy within a couple of feet while task loaded. That's why they teach new divers to NEVER HOLD YOUR BREATH.

... Bob (Grateful Diver)