Is exhaling too slowly during a CESA a concern?

[davidbaraff]

We did a "simulated" practice CESA in our pool class (pool is only 12' deep, so we swam from bottom to top across the pool length to simulate it) and will be practicing it for real during our ocean OW dives.

I know of course that one must exhale continuously on the way up when doing CESA. My question is, as long as I am trickling air out of my mouth, is there any danger I might do it too slowly and still riska lung injury?

The reason I ask is that I observed that on land, not under stress, I can take a long breath and *very* slowly exhale it over a 40-45 second interval without much difficulty. Assuming I started around 30-35' under water, and came up at the mandated 1 foot/second ascent rate (for CESAs), I could (unless i'm panicking) easily stretch that ascent out for a full 30 seconds without starting to feel like I need air.

So anyway, this got me to wondering if you every have to worry about exhaling too slowly on an ascent.

 

[Gombessa]

I was taught that you just need to keep your air passage open. People are taught to exhale constantly or make an "aahhhh" sound in order to ensure this, but technically, even if you don't exhale, but keep your airway open, expanding air should have an easy avenue of escape, and you'll be fine. You may notice that if you exhale slowly, you might still have "burps" of air come up while you ascend. That's what's happening.

In short, if you're exhaling at all, you should be OK.

 

[wedivebc]

It is not a concern as long as you keep the airway open. Even breathing in during a fast ascent is possible without damage as long as you keep the passage open.

 

[jpcpat]

Yup, an open airway is the key. blowing bubbles just proves that your airway is open.

On your checkout dives, your instructor will be looking for a continuous stream of bubbles. If you stop exhaling, your instructor will stop the ascent immediately. We don't take risks with students.

 

[Scubakevdm]

It's actually possible to blow bubbles with a locked throat. It is not possible however, to make an ahh sound with one. I know it's nit picky... I'm just saying.

 

[scubatoys]

It's actually possible to blow bubbles with a locked throat. It is not possible however, to make an ahh sound with one. I know it's nit picky... I'm just saying.

Not really... It's the air passing by the vocal cords that makes the hum. Stick your face in the water and hum without bubbles... can't be done... I've tried! Or just close your mouth and pinch your nose and hum. You will see your cheeks blow up as that air has to go somewhere! And you can't keep a hum for longer than a second or so in your cheeks!

Ooops... read that wrong.. Yes, you can blow out whatever is in your mouth... but for some reason I read your post as you could humm... man... I've got to go diving!!!! Soon!

 

[Jim Kerr]

I was taught to make the ahhh sound too which is "suppose" to be perfect so that you don't let your air out too fast or too slow. At the time I took my OW class the ascent rate being taught was 60 ft per min, but I thought they were now teaching the much slower rate of 30 ft per min, which most divers I know go by and for which most cmputers are programed.

 

[davidbaraff]

I was taught to make the ahhh sound too which is "suppose" to be perfect so that you don't let your air out too fast or too slow. At the time I took my OW class the ascent rate being taught was 60 ft per min, but I thought they were now teaching the much slower rate of 30 ft per min, which most divers I know go by and for which most cmputers are programed.

It's 30'/minute for a normal ascent, but 60'/minute is allowed for a CESA.

(Of course, in an absolute worst-case situation, I'd take an even faster ascent than drowning...)

 

[Jim Kerr]

It's 30'/minute for a normal ascent, but 60'/minute is allowed for a CESA.

(Of course, in an absolute worst-case situation, I'd take an even faster ascent than drowning...)

You can die from that too just as easily. At 60 fpm you should have enough air to make it to the surface since air expands as you ascend.