Holding your breath on ascent...

[JanK]

Sure, the pressure drops from 1 bar at sea level to to 0.75 bar (3000 metres equivalent). A 0.25 bar or 2.5 metres of H2O column. Check out the picture of bottle on this page.

 

[Thalassamania]

Don't know about commercial aircraft, but a Bearcat can go from the deck to angels ten in 86 seconds and modern jet fighters are a lot quicker than that, especially if they kick their blower.

 

[JanK]

Highly impressive indeed: Time to climb to a height of 3 000 m : 25.37s
Date of flight: 27/10/1986
Pilot: Victor G. PUGACHEV (USSR)
Course/place: Podmoskovnoe (USSR)
Aircraft: Sukhoi P-42

That's from a standing start, including a few seconds acceleration down the runway...

I haven't been able to find newer data (I suppose the military wants to keep it under wraps). But even with this beastie you could certainly tear up your lungs.

 

[elmer fudd]

Hmmm, and I was thinking holding my breath on ascent might be a good way to expand my lung capacity. You know, start out small holding my breath at 3' and then gradually build up to 50 or even 100'. Give me a chest like Dolly Parton it would.

 

[dumpsterDiver]

Hmmm, and I was thinking holding my breath on ascent might be a good way to expand my lung capacity. You know, start out small holding my breath at 3' and then gradually build up to 50 or even 100'. Give me a chest like Dolly Parton it would.

It just might work! Sounds like you got the brains of that large breasted blonde already.

 

[acwest]

I can't find it, but I'd swear someone cited a source that said words to the effect of - breath holding over as small an ascent as 10' was enough to cause pulmonary edema . . . In other words, damage could be done before you would feel anything.

This one cites pulmonary edema and hemoptysis in healthy breath-hold divers to 3 to 6 m.
Pulmonary edema and hemoptysis after breath-hold diving at residual volume -- Lindholm et al. 104 (4): 912 -- Journal of Applied Physiology

A friend of mine was once involved in the recovery of the body of a diver who died from a barotrauma-induced embolism while diving in a wreck called the Waome. The diver managed this inside the galley of the ship, which was certainly no more than 8 feet tall. I don't believe there is any indication as to whether or not they felt the pressure change in their lungs, though...

 

[Thalassamania]

I'm not sure that the percentage change available to you in an 8 foot ascent at 60 feet, or so, will do it.

 

[tfsails]

So here is a related question.

If you hold your breath during a regular commercial flight ascent (which is up to 8'000 feet or so pressure altitude) will you have a lung over-expansion problem? I think this is physically impossible because of the time it would take, but it is an interesting question.

You have to go up 18,000 feet to reach 1/2 atm in air. Therefore, an 8,000-ft cabin altitude gives you 89% of sea-level pressure, so your lungs wouldn't expand much if you could hold your breath that long. Remember that air is compressible and water is not, hence the difference.

As far as holding your breath under water is concerned, going up 10 ft from 100 ft is vastly different than going up 10 ft from 30 ft. The shallow end of the depth spectrum is where you see the greatest pressure change per foot of depth. I wouldn't advise holding your breath at all.

 

[g1138]

I understand that under no circumstances should anyone hold their breath while ascending however it seems that there are a few posts floating around that suggest that for whatever reason this still happens. I'm not trying to blame or shake my head at these people rather my intent is to further understand what happens.

When I try to to simulate a breath hold on ascent while on dry land (by breathing in as deep as I can) I can feel my lungs expand and my chest area feels tight. I'm not about to try this under water so I was wondering if anybody knew if you would feel the same sensation if this ever happened while diving. I can only imagine that you would feel pain as your lungs over expand. Anybody have any insight on this matter? Experience or hear-say?

These are the things that keep me awake at night...

The difference between trying it on land and actually doing it in the water is your chest volume and diaphragm.
On land what you're doing is "opening" your diaphragm as far as you possibly can, there by increasing your chest cavity to it's fullest. So that tight sensation you feel is your chest, not your lungs.
Your alveoli in you lungs probably don't have as many nerve endings as your chest, maybe even none, zip zilch etc.
Keep in mind that an over expansion injury from a breath hold ascent injures the alveoli first, not your diaphragm or chest. So this is probably why no one feels it happening until after their alveoli rupture.

 

[maljan]

Have you ever done the experiment of filling a plastic bottle at 10 meters below, seal it and let it surface. You will be amazed what the expansion of air can do!