Why does it feel like it's harder for me to empty my lungs at depth?

[eckoback]

I still consider myself to be a relatively newish diver at around 100 dives, and up until now, I haven't really paid any attention to my air consumption. I'm never the first to surface while just "breathing normally," so that's been good enough for me. I recently started to pay more attention to my breathing pattern because you can never stop learning to improve different aspects of your diving, right?

I've been experimenting with various breathing rates or techniques like emptying out your lungs more to reduce CO2 absorption. Thing is, I found that emptying my lungs to be way easier at shallower depths. For example, I can slowly exhale and empty my lungs for 10+ seconds at around 40-50ft, but when I go deeper to 60-70+ft, I struggle to even exhale and empty my lungs at like 4-5 seconds. And when I go deeper and try to fully empty my lungs, it feels like I have to catch my next breath and have to inhale sharply -- it's not a "smooth" breathing loop if that makes sense.

I'm trying to recall back to my OW cert and am struggling to figure out why this is the case. Air is denser at depth, but shouldn't that only impact your inhalation and not exhalation?

 

[Lorenzoid]

You probably know this, but you shouldn't be "emptying" your lungs. Even the common advice to breathe "deeply" isn't quite accurate. I think "fully" may be the most accurate description. Inhale fully but not in an exaggerated/unnatural amount, then exhale to that same extent. It should feel natural, little different than you breathe on the surface when you're thinking about breathing.

 

[scubaozy]

I still consider myself to be a relatively newish diver at around 100 dives, and up until now, I haven't really paid any attention to my air consumption. I'm never the first to surface while just "breathing normally," so that's been good enough for me. I recently started to pay more attention to my breathing pattern because you can never stop learning to improve different aspects of your diving, right?

I've been experimenting with various breathing rates or techniques like emptying out your lungs more to reduce CO2 absorption. Thing is, I found that emptying my lungs to be way easier at shallower depths. For example, I can slowly exhale and empty my lungs for 10+ seconds at around 40-50ft, but when I go deeper to 60-70+ft, I struggle to even exhale and empty my lungs at like 4-5 seconds. And when I go deeper and try to fully empty my lungs, it feels like I have to catch my next breath and have to inhale sharply -- it's not a "smooth" breathing loop if that makes sense.

I'm trying to recall back to my OW cert and am struggling to figure out why this is the case. Air is denser at depth, but shouldn't that only impact your inhalation and not exhalation?

It is due increase of work of breathing . It is more relevant for for deep/technical diving, so usually in recreational OWD level manuals will not cover this, at best you would find a simplified statement such as "air will get denser" thus will become harder to breathe.
What you are asking is answered here: Start from 21:00.

 

[Scuba Client]

I still consider myself to be a relatively newish diver at around 100 dives, and up until now, I haven't really paid any attention to my air consumption. I'm never the first to surface while just "breathing normally," so that's been good enough for me. I recently started to pay more attention to my breathing pattern because you can never stop learning to improve different aspects of your diving, right?

I've been experimenting with various breathing rates or techniques like emptying out your lungs more to reduce CO2 absorption. Thing is, I found that emptying my lungs to be way easier at shallower depths. For example, I can slowly exhale and empty my lungs for 10+ seconds at around 40-50ft, but when I go deeper to 60-70+ft, I struggle to even exhale and empty my lungs at like 4-5 seconds. And when I go deeper and try to fully empty my lungs, it feels like I have to catch my next breath and have to inhale sharply -- it's not a "smooth" breathing loop if that makes sense.

I'm trying to recall back to my OW cert and am struggling to figure out why this is the case. Air is denser at depth, but shouldn't that only impact your inhalation and not exhalation?

Are you a chain smoker? What is your overall fitness level? Age group? Take a yoga class.

 

[Zef]

It is due increase of work of breathing . It is more relevant for for deep/technical diving, so usually in recreational OWD level manuals will not cover this, at best you would find a simplified statement such as "air will get denser" thus will become harder to breathe.
What you are asking is answered here: Start from 21:00.

That was a very informative lecture....thanks for posting it.

-Z

 

[TMHeimer]

I think one of the reasons breathing is supposed to be harder at deep depth is the water pressure around you affecting your chest/lungs. I've not noticed this. Maybe the effect is very slight.

 

[Blackcrusader]

I am not sure what you mean at depth? 25m? 30m? 35m? 40m?

Here is a video of me at 30m depth. I do a slow controlled intake and a slow exhale. I do not notice the effort anymore than I do say at 15m or 10m depth. Does your regulator have an adjustment for gas flow?
I am in the blue shorts.... count the time between bubble trails.

 

[Lorenzoid]

I think one of the reasons breathing is supposed to be harder at deep depth is the water pressure around you affecting your chest/lungs. I've not noticed this. Maybe the effect is very slight.

The air in your lungs is at roughly ambient pressure, isn't it? No, I believe the effect the OP is referring to is due to the increased density at depth.

 

[TMHeimer]

The air in your lungs is at roughly ambient pressure, isn't it? No, I believe the effect the OP is referring to is due to the increased density at depth.

Yes, agree I think it is a question about density. I did read somewhere that increased pressure around you at depth does make it slightly harder to inhale (even though what you inhale into your lungs will be at the ambient pressure). Makes breathing a little more restrictive I think. As I said, I can't recall noticing that when deep.

 

[dmaziuk]

Air is denser at depth, but shouldn't that only impact your inhalation and not exhalation?

No, it works both ways. In fact it should affect your exhalation more because the reg is blowing compressed air into you -- personally I find it harder to breathe on the surface, for the first few breaths off the reg when I have to actively suck air in after an hour or so of not having to do that.

Out of curiosity, what's your respiratory stats/background? I don't feel any extra breathing effort at 60-70' but I've swimmer's lungs that even allergies and a couple of decades of smoking couldn't break. :fingers crossed: