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Research: How to reduce lung residual volume?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

What is your lung residual volume?

  • less than 1l

    Votes: 0 0.0%
  • between 1-2l

    Votes: 10 62.5%
  • between 2-3l

    Votes: 4 25.0%
  • between 3-4l

    Votes: 2 12.5%
  • between 4-5l

    Votes: 0 0.0%
  • more than 5l

    Votes: 0 0.0%

  • Total voters


New Member
May 10, 2007

Since residual volume is a very important factor and has impact on deep dives, I would like to know if anybody already tried an exercice, technique, or method that can acctualy reduce lung residual volume?

I put here the results of my exams for analisys:
  • VC IN: 7,09l (vital capacity)
  • RV: 3,12l (residual volume)
  • ITGV: 5,89l (intrathoracic gas volume)
  • TLC: 10,41l (total lung capacity)
I invite you to share your exams results also for further analisys.

Best regards,
For deep dives, the flexibility of the diaphragm (and the ribcage) is actually more important than the RV. Well, to certain extend the two aspects are related, but great diaphragm flexibility does not necessarily mean you will be able to exhale actively more to reduce your RV, while it will definitely help at deep dives when the diaphragm flexes passively.

Most freedivers use Uddiyana Bandha (and other similar yoga exercises), and packing stretches (positive and negative) to improve the elasticity of the diaphragm (and the ribcage).

EDIT: on the other hand, excessive (positive) packing is suspected that it may cause over-stretching of alveoli, with the consequence of loss of elasticity of the tissue, hence inability to shrink fully (increased RV), and consequent possible collapse of alveoli at low exhale volume. The collapse of the alveoli in depth would not be a big problem from mechanical point of view, because the alveoli gets inflated back during the ascend, but it may lead to pressure build in the enclosed cavities and to possible rupture of the alveoli tissue at re-inflating of the collapsed alveoli.

I am not sure if this is confirmed medically, or whether it is a pure speculation, but I heard multiple times the claim that heavy packers may have problems with RV.

Also an experienced osteopath may help with skeleton/musculature manipulations to unblock certain limitations and considerably help to increase VC and decrease the RV. When you look for an osteopath, you best search one that works with swimmers or athletes - the manipulation for unblocking pulmonary capacity is often used by them.
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I've no idea what my residual volume is, but.

As trux points out, rv is a little bit different concept medically and in diving.

In medical sense, it means the volume left after you exhale fully.

In diving sense, you can go well below that by "cheating", ie using the external pressure or without the pressure change, using negative packing.

This latter definition is more interesting to us. It doesn't have that much to do with medical rv, but more with - as pointed out - flexibility of the diaphragm and other muscles and tissues around the chest. So a person who does a lot of negative stretching etc might get exactly the same result in an exhale test, but in diving, it makes a world of difference.

Would be nice to measure sometimes, this is a pure guess, but comparing to what I can pack in, I'd say when properly stretched etc I can remove 1.5-2 liters of air from my lungs with negative packing after reaching rv - comparing to the average rv that leaves "not a lot" in the lungs - and makes quite a difference in equalization.

How ever, off season I can hardly do 4-5 negative packs before I feel the squeeze.

Hmm, sorry I kind of didn't answer the question posted, but assuming you're interested in this from a diving point of view, I guess this makes some sense.
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Hi Trux, Jome thanks!

i found some interesting links about Uddiyana Bandha, Kudalini and Yoga which seems related:
Some pending questions:

1 - It's curious how yoga exercices are so much times related to advanced freediving, but do you know if there is a method, exercice or technique "non-yogic" to reduce lung residual volume?

2 - interesting to know like trux said that: "osteopathy may help with skeleton/musculature manipulations to unblock certain limitations and considerably help to increase VC and decrease the RV". Anyone tried that with significant results?
1) Yes, as we already wrote - packing stretches will help. Also plain rib cage and diaphragm stretching exercises will help

2) Yes, we had an osteopath studying the effect on several members of our club. However, it was rather focused on increasing the maximal pulmonary volume, than reducing the RV (though it is certainly related). Generally, there was some increase of the volume, but the difference was behind the results at swimmers or athletes. Probably because most freedivers already unblock themselves better (due to training, relaxation, and stretching) than sportsmen in other disciplines. Unfortunately I did not participate in the project, and did not see any written results of the study, but will try to find out if I can still get into contact with the osteopath to ask about it.

Certainly you can do "non-yogic" stretches. Simply exhale as empty as you can - that's already a pretty good one. Then "pull up" the diaphragm for extra stretching.

I prefer to do them lying on my back. I start with my knees bent, exhale, pull the diaphragm up and the for additional stretching carefully straighten the legs one at a time and finally reach my arms up (finswimming style). This starts to get pretty easy after a week or so (doing it every day), and then I start to add negative packing after the exhale, increasing the amount of packs gradually.

You don't need to do super long breath holds and in fact I recommend against that, because it is really easy to bo/samba doing statics on empty lungs. 15-20 seconds per stretch, 2-3 stretches should get you good progress.

You should feel the stretech, but not pain - so if you do, take it slowly.

In addition to this, basically any kind of mundane upperbody stretching will benefit you tremendously.
Thanks Jome,

Seems simple and effective like i wanted without all that yoga stuff.
After 3 years of FRC diving, with no packing or inhale dives, my residual volume has decreased by almost 40% according to my own measurements. I now believe that I may have one of the smallest residual lung volumes in the history of freediving.
Interesting, Eric! (though not really surprising). What are the values before and after? And how do you measure the RV yourself? I thought that relatively expensive equipment was needed for RV measurements. As far as I know, it is usually calculated by gas analysis - for example the change caused by washout of nitrogen. Or is there any affordable measurement device available on the market?

And did your total lung capacity also shrink in similar way, or is it unchanged?
Two methods you can use to estimate RV or at least changes in RV include:
- Changing ratio of full exhale static to FRC static
- Change in ballast required to reach neutral buoyancy at different depths without wetsuit
- Changing depth at which a full mouthfill is possible

Putting all the data here would take a long time. However, to consider some examples:
- In September 2005, starting my dive on FRC volume, I could perform a full mouthfill at a maximum of 9m of depth. Now, that has increased to 17m.
- In September 2005, my full exhale static was about 2'50". Now, my full exhale static is about 1'50", although my FRC static is about the same as it was in 2005.

I also know that my lung volume (inhale) without packing has decreased considerably, and my max volume with packing has decreased dramatically.

The RV was recorded in tests in 04 and has probably increased since then.
Is the TLC full inhale + packing + rv?
Bill presented a method to measure RV a few years ago. Descend to 10 m (1 atm), exhale fully, return to the surface and exhale again into a container that you can measure (upside down milk carton for example). RV is double the measured volume. You can do it in a pool with different math. Elegant, makes sense, but I get suspiciously low numbers when I try it.

Bill presented a method to measure RV a few years ago. Descend to 10 m (1 atm), exhale fully, return to the surface and exhale again into a container that you can measure (upside down milk carton for example). RV is double the measured volume. You can do it in a pool with different math. Elegant, makes sense, but I get suspiciously low numbers when I try it.

Given that exhale spirometry gives noticably lower results after a freedive, I'm not surprised that you get low numbers.

Here're my results from a research hospital:
TLC: 7.50
Packed: 8.38
FRC: 3.22
RV: 1.08

RV measured using helium gas analysis. Full report for those that understand is attached. Pre is my normal inhale, Post is with packing. There's also pressure measurements in there that suggest that the air in the lungs post-packing is actually compressed.


  • Spirometry Results.pdf
    11.6 KB · Views: 324
Hi Eric,

It would be interesting to see your pulmonary function report (PFR). Probably you already have less than 1l RV.

PS: I will digitalize the results of my (PFR) in the following days.
Hi Watts,

I made two pulmonary function report (PFR) in 2004 and 2007, but the results are quite the same, even so i had increase my depths in 20m (from 30 to 50).

But I think that with specific tranning we might reduce RV a lot (needs research).

And yes TLC (total lung capacity) = RV + VC IN + Packing (but during my test they don't allow packing, only a continuous full inhale)

VC IN - vital capacity or full inhale (continuous)
RV - residual volume
ITGV - intrathoracic gas volume (maybe equal to FRC?)
TLC - total lung capacity
Hi Connor,

That's a very interesting method to mesure residual volume without having to pay for it, not very accurate, but probably very effective if you want to compare between two dives or after streching/diving exale methods as described in previous posts.
how to measure residual volume:
dive to 10 m (2bar pressure)
exhale completly
now in your lung is 2*rv because it is 2 bar at 10 m
surface again and measure how much air you exhale
you exhale 1*rv, 1*rv stays in your lungs

you can do this also at 4 m in a pool, but than you exhale 40% of rv

you can measure it at the surface like this.
a friend fills a 2 litre bottle with water and hold it closely under the surface,
now you have to exhale thru a tube into the bottle. the air is collected there and you can measure it.

hape this is understandable,

Amazing Chris, 1.08l residual volume!

Any special tranning or genetic?
Always been a swimmer, been fit most of my life, but mostly just lucky genes probably.

I also lived at altitude for a long time and did diaphamatic inflections for the hell of it before I knew what they were. That may have helped too.
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