Expiratory Peak Flow

[lizardland]

Once a month a nurse comes into work to give medical checks for those that want it. I've just had one done and had my expiratory peak flow measured. It came in at over 700l/min, 1.65 times the predicted value. She was quite surprised by this and asked what sports I did.

I've noticed some definite changes in my lungs since I started freediving but I've never had any measurements done so i don't know what it was like before.

So... does freediving cause such big changes or would my peak flow have been this high regardless?

Cheers,

Stuart

 

[Mullins]

Packing seems to change this measurement a fair bit - enough for doctors to start giving you concerned looks anyway. I had a lung function test a few months back to see how much volume I gained through packing. On a normal inhale I had a very large VC (10.4l) but quite a low PEF (peak expiratory flow), at 605l/min. With packing, I gained an extra 3.6l VC and the PEF also went up, to 810l/min.

I think that PEF depends quite a bit on elastic rebound. If you pack regularly, a normal inhale will not be anywhere near your ribcage's elastic limits, and so you won't get a very high rate of flow in that first second because you're really only relying on muscular force to blow the air out. Then when you take what is effectively a 'full' breath using packing, you get that elastic assistance back.

Given your results I'd assume you don't pack, or at least not much? Freedivers often seem to have weird spiro measurements, as we use our ribcages/diaphragms a lot more intensively than many others. I think that knowing how to control those muscles makes quite a bit of difference, rather than outright physiological change.

 

[naiad]

The predicted value for my peak flow is 472, but it has been 600. I didn't pack for the peak flow measurement.

Lucia

 

[OceanMan]

On a normal inhale I had a very large VC (10.4l) but quite a low PEF (peak expiratory flow), at 605l/min. With packing, I gained an extra 3.6l VC and the PEF also went up, to 810l/min.

You're saying that with packing you have 14 L of VC ??? Wouuaaooo!!! Are you a giant or what?

What is your residual volume?

Cheers

 

[Mullins]

Yep - I'm a tall skinny bugger That was with max packing, for actual dives I'd estimate I only take down about 12l or so. Unfortunately I haven't been able to get my RV measured, I would like to know though...

 

[cdavis]

Hi Mullins,

You can get a pretty good idea of RV from an idea posted here a while back. Pick a known depth, say 33 ft, exhale all the way at that depth, come to the surface and exhale into a jar open at the bottom, measure the volume (and do whatever math works if you pick a depth less than 33). Thats your RV. Do this 4 or 5 times an you will have reasonably accurate estimate.

Wish I had your lungs.

Connor

 

[Narsil]

Yeah, Dave (Mullins) has an awesome set of lungs.

When he packs fully before a dynamic, his back has a serious humpback whale look! He needs a pretty hefty neck weight to allow him to sound effectively :t

 

[Mullins]

That test for RV that Connor mentioned makes sense, we must try it next time we're up at the lake. Lung stats sort of seem incomplete without an RV value.

 

[Stavros]

Guys why not do a proper full spiro test? its easier and much more accurate.
I did a full going through a couple of weeks back including an ergo test to get Max VO2.

In order to get RV you do a measurement inhaling Helium (there are a couple of different ways using different gasses) and they get your RV.

One thing I noticed is that since these RV measurements are done in a chamber where you are sitting down you get a lower VC than your max since you cant get the diaphragm to extend down fully. I got my VC this way at 6.58lt and standing up it was at 7,45lt. Thats without packing...half packed (something like a static pack) it got way over 8lts but the gizmo only measured up to 8lt so we stopped there. My predicted value was VCpre 4,65lt (I am 1,71m) The residual volume was at 1.05lt which was something like 0,65X of what the expected values were.

So all in all I think we prove that the norm does not hold for freedivers who are trained in fully utilising their lungs/diaphragm.

My peak flow was at 14,2lt/sec ie 852lt/min... One thing I noticed while doing the measurements of peak flow was that as I am used to controlled exhalles I was not able to really exhale at full strength...some control was always there.

Cheers Stavros

 

[naiad]

I measured my VC a while ago, with and without packing. Not totally accurate, but...
[ame="http://forums.deeperblue.net/showthread.php?p=448517#post448517"]lung volume measured, +3 litres with packing[/ame]

 

[Waterysmile]

Interestingly, wikipedia states that Peter Reed, a rower, has the largest recorded lung capacity at 9.38 litres. It appears that more than one freediver should beat that.

Naiad - so you have the lung capacity of an average-sized male (like me actually); you squeeze all that air into that slender frame of yours - take care when packing (and take firm hand of organisers at static comps and get over 5 minutes! I was pleased to get 4 minues dry for the first time yesterday).

 

[Waterysmile]

When I had my freedive medical at the end of September my Peak Flow was 450. This week I went along to an asthma clinic and the Peak Flow was 560 (predicted 600) so I was very happy with that. I took in a good lung full but I do not pack (yet!).