Do you really have to exhale while ascending?

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Another anecdote...and a slightly different caution. Some time ago I read about a very experienced diver who was holding onto the hang bar at 10' on a boat. A rogue wave caused the bar to quickly ascend and he suffered AGE and later died. I generally don't use the hang bar, preferring to practice buoyance control on the stop. But, if I do, I only touch it or hold on with a finger. I see too many divers with a death grip or sitting on the bar. Not a good practice in my book.
 
What everyone here has posted so far is absolutley 100% correct the only little tid bit that I have to offer is that you don't need to be breathing out during the whole asscent but that by keeping a normal breathing pattern you are at least keeping an open airway. Any air that expands in your lungs during the inhale would expand and release back up your throat before it would cause any injury, but when holding your breath you actually close off that airway. That is why when doing reg recovery drills or a CESA Simulation you are either blowing bubbles or making an aww sound becuase both of those require that you not close off your throat.
 
To avoid an embolism on ascent, you have to allow the expanding gas in your lungs to escape.

Steady breathing is a way to accomplish this.

It's the exhalation part of the breath cycle that does the job. We learned this when we did our CESAs in OW training (remember?--say "ahhhh" all the way up).

Another way is simply to keep the airway open. That is, don't lock your throat when you breathe or hold your breath. That's actually what the "ahhhh" of the CESA is accomplishing.

Keep in mind that keeping an open airway prevents only an embolism. You want to keep from getting bent, too, so always be mindful of your ascent rate as well.
 
You don't have to exhale when ascending....... but it is going to hurt one way or the other. Boyle says so. :shakehead


When I started out, I did a discover scuba thing. I bounced a lot finding myself between the surface and the bottom (40ft or so) several times. I had no idea about holding your breath. I think I got lung over expansion problems. Afterwards, my lungs hurt, especially when inhaling deeper. It took a week, maybe two to subside. It is easy to get hurt when holding your breath and ascending.......
 
The shallowest recorded lung overexpansion injury was in three feet of water.
 
These are all great comments, some of them very enlightening...and alarming. I have "bouyancy control" on my list of things to accomplish this dive season. I think I will make the first weekend all about this.
 
Here's an interesting test to try. It might even be fun, but definately educational. Take a balloon down to 10ft and fill it with air almost to the breaking point if you can judge it.

Tie it closed and let it go and count 2 seconds. See what happens to the balloon. You're looking for two things. One, does it burst or expand exponentially within those 2 seconds. Second, how far does it go?

I'll be it reachs the surface in those 2 seconds.

Purpose of the experiment is to show just how far you can actually go on a breath hold in 2 seconds and to see just what your lungs are going through in the last few feet of ascent.

Besides, playing with balloons underwater is fun. :D
 
Another cool experiement....

Last summer I was with a bunch of teenagers doing AOW. We examined a nalgene bottle at the surface. If you have ever handled one you know one can barely move or flex the hard plastic as they are super strong. With all my strength I could hardly bend it at all. We then took it down intending to see what would happen at 100 feet...by 35 feet it was crushed. That 1 ata of pressure change is VERY powerful.
 
Very cool ideas. Is it difficult to blow the balloon up underwater?

And could you carry some in your BC pocket to blow up in case your BC had a hole? No, no, forget about it! What was I thinking?

The first, best thing to do is get your weight/bouyancy requirement figured out for an almost empty tank and 15' depth.
 

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