Functional Residu Volume - FRC - diving for beginners?

[Kars]

Is FRC diving recommendable for beginners?

In search for insight into this question I've opened this thread so we can explore and discover weather FRC diving is or can be used by beginners. Would starting with FRC yield long term success? Does it pose additional safety concerns? Is FRC is already part of today's beginner freediving curriculum? If so how is it implemented? Why Should it be or not be part of the beginners freediving course?


I think that before we can start answering the question we should first draw up a quick list of the main merits of FRC diving.

- Feel invited to supplement and correct the following short list.

FRC merits.

1) Better relaxation.
2) Better dive experience.
3) More diveresponse.


Also I think we should look at the challenges FRC diving poses.

- Feel invited to supplement and correct the following short list.

FRC Challenges.

1) Earlier and stronger onset of the urge to breath.
2) More critical and difficult to sense end of the dive.
3) Less numerical performance.

I'm sure we can come up with a much more pro's and con's to list, from which we can draw the lessons and start to formulate if, why, how FRC diving is for beginners.

 

[azapa]

Kars, great list and initiative. In the risks side I would say lung or trachea squeeze as a big one, even in 5M of water. It also happens fast and may be hard to detect in the moment for a new diver.

Regarding being part of any training organizations CV. I would say that AIDA/AA only mentions it's existence by chance before level 3, and is not part of the curricular material. I am guessing on Aida, but am sure on that regarding AA. An independent instructor body like PFI or FII: the do some head down EQ practice empty lung in a 3m or so pool on Level 2.

 

[cdavis]

Great thread idea. Thanks to Kars, Azapa and Fluppo for starting the conversation.

Also a hard and complicated subject. I started to comment a couple of times, each time changing my thoughts. Seems like we need to do a little defining of what we mean by FRC diving.

There is:

Diving at FRC, a specific defined condition of relaxed exhale. However, the volume of air at FRC varys a bunch between divers. For me, its almost empty. From conversations with others, I think a lot of divers are diving exhale at a larger volume than their personal FRC.

Diving half lung or thereabouts. I think this is more common. For some divers, this would include FRC volume.

Diving forced exhale, empty, can include reverse pacs. I think of this as a completely different category, definitely not for beginners. 'this is how you can get squeezed in 5 m. If your FRC volume happens to be very low, FRC can come pretty close to a full exhale dive, with the associated dangers.

Other categories?

We need a better word to define FRC/half lung/exhale diving.

There also needs to be more awareness than diving less than full lung is not about a specific amount of exhale, its about having small enough lungs to aid fast kick in of dive response and adjusting your weighting/dive style so that the first part of the dive is basically a static.

With the above comments, I'll argue that diving around half lung is something that can be taught to inexperienced divers, either as an intro to freediving or as a shift from full lung. Like almost anything else in freediving, it needs to be explored carefully at first and with good safety, but I don't see it as fundamentally different from leaning to dive deeper than say 70 ft, full lung. No question it is more complicated than grabbing some gear, inhaling and going for it, but so are most things in freediving.

Diving with less than a lung full sharply reduces a divers performance initially. It takes more than a little practice to see longer(it gets much longer) dive times than diving full lung and especially it takes time and practice to get depth back. Diving at something over half lung should substantially reduce the potential for nasty surprises in a beginner. After doing enough practice to see the longer dive times than on full lung and especially to get depth back, can a diver be called inexperianced?

Much more to comment on, more later

Connor

 

[Kars]

Good and fair questions Connor.

Indeed let's get the definitions sorted out before we proceed.

What defines for me FRC?
Indeed it varies with the person, the flexibility and position in of out of the water - vertical, horizontal, back floating, belly floating.
What defines for me FRC is after doing a normal slow inhale, a passive exhale. What remains is my FRC volume.

Sitting strait up on land I estimate that my passive exhale/FRC is about 2/5 of TLC, and my forced exhale (without reverse packing) is to less than 1/6 of TLC. My TLC is about 6 Litres.

I would propose refining the FRC definition as:
FRC = the amount of air remaining in the lungs after a passive exhale sitting strait up on land.

But now I'm remorseful thinking about what the FRC pioneers may think of this, so let's get back to basics, how did they define FRC?

 

[cdavis]

You could define FRC diving like that or similar if everybody had the same volume. Pretty sure they don't. My FRC volume at rest sitting up dry is slightly less than yours and my lung volume is less.

Even if you could define it like that, I don't think that gets to the essential of exhale diving, dive reflex and early static. If you can get all or most of the benefits of exhale diving from a larger inhale than FRC, why not?

What is your wet FRC volume?

When you are diving FRC and using FRC dry volume, how do you determine it?

Out of time, gotta go.

Connor

 

[azapa]

for me and many here (not FRC experts) FRC is sinking from the surface or staying down on shallow dynamics without lead with just a pair of shorts or speedos on. That is probably way lower than 1/2 lung, but an easy gauge.

 

[Herup]

Kars and Conor, I completely agree with your definition of Functional Residual Capacity: Relaxed exhale (or relaxed inhale from somewhere in Expiratory Reserve Volume) being in an upright position with the spine straight and out of the water.

But Conner, I think you are also right that there is no "truth" in this particular physical condition or amount of air in relation to ones individual physiology when trying to achieve the benefits of the various dive responses as efficient as possible in relation to the decided objective.
So regarding the the blurry definitions and various terms we have been using so far, Sebastian Näslund suggest another term in his really inspiring story from an older Sebastien Murat course in Sweden: DR-diving or dive response diving. Quite a good suggestion since the benefits from the dive responses are really the matters at interest; what say you?

Best regards
H!

 

[cdavis]

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

 

[cdavis]

Ok, I'm on somebody else's computer. Sorry for the screw up

DR diving. It gets right to the nut of what we are trying to encourage. I like that, but it seems like the name should give some indication that we are diving less than full lung. Maybe its like "FRC", its ambiguous sounding enough to force an explaination that we are diving below full.

Looking at Kar's numbers, 2/5 of full is 40 %. That's close enough to 1/2 and clearly not empty lung. I'm diving about 60 percent. With smaller lungs, that is pretty close in volume.

Azapa, great example of the confusion we are encountering. That volume is pretty low. I think I would be almost empty. Not something I would want to attempt for anything other than pool training or a short, shallow warm up. To me, that doesn't fall in the range of lung volumes we would use for normal exhale diving.

Is their any consensus that exhale/FRC/half lung/DR diving is not done at or close to empty lungs?

 

[efattah]

First of all, there is no point in looking at the actual lung volume, since one person's full exhale volume can be more than another person's full inhale. So all that matters is percent or ratio.

Since there is no easy way to measure residual volume, I suggest ignoring it and looking at FRC volumes as a percentage by FVC (vital capacity, not total capacity).

In my case, FVC with no packing is 7.2 to 8.0L, depending on my level of training. That is the amount I exhale into a spirometer. It does not include residual volume. Sitting straight on a passive exhale, my true FRC (VC) volume is about 3.25L, again exhaled into the spirometer. If I exhale fully, obviously I exhale 0.0L into the spirometer.

Seb Murat, pioneer of the method, himself said he had an FRC volume of about 5.25L. I think that included his residual volume.

While doing 'FRC-style' dives in the ocean, I tried diving at everything from below FRC (around 2L VC) all the way up to 6.5L, somewhat below full inhale. For me the best results happened around 4.5L to 6.0L, which is about 56% to 83% of full inhale, depending on how you calculate it.

In my case, I would pack at VC=10.40 to 10.95L depending flexibility. So the volume I would dive at on FRC-style dives was as little as 41% of the volume I would pack, but generally around half. That was my main rule of thumb. My best results came with a VC that was half of my VC with packing.

In my mind, anything less than a full inhale starts to fall into the FRC-style category. Anything below actual FRC is more of a negative pressure dive, where the actual depth is severely limited by lung/trachea squeeze.

I think all beginners should inhale. However, a beginner has a very poor ability to inhale. Most beginners, attempting a 'full' inhale, are inhaling perhaps not more than 70% of their actual vital capacity, so even telling them to inhale to the max is actually bordelining into the FRC-style of diving. I taught my wife to dive-- she has a very small lung capacity of about 3.4L. When diving she inhales, but doesn't strain the inhale, probably getting around 2.9L.

In my case, maximum constant weight depth varies with lung volume:
0.0L (full exhale) 31m limited by squeeze
5.0L VC 72m limited by BO
10L VC 100m, still not at limit

However, for 'fun' diving, I generally dive around 5L to 6L VC, unless I am diving in shallow water, in which case I sometimes dive at true FRC. If I am diving for fun over 40m, I will generally pack my lungs. I have done 'fun' FRC-style dives at 5L VC to 45m, but this is very risky and I once had a samba, since it is nearly impossible to judge the air supply and it feels like russian roulette.

 

[Don Paul]

Great thread guys, sorry a little of topic... but I seeing spirometer prices in the $200.00 range here in the states. Are there deals out there ?
At my advanced age, 58 years young I would like to start measuring lung volume. Thanks in advance.
Cheers, Don Paul

 

[cdavis]

I think Eric has expressed the general principle pretty well. Whatever we call it, DR diving starts at any significant amount of exhale below full and stops as exhale approaches empty. Given the variation in divers and styles, its probably not possible to get much closer than that. I think I'll adopt "DR diving" henceforth. That should REALLY confuse folks. Truly, its not the amount of exhale, its what kicks in DR fast and conserves 02 until it does.

I think the amount of air in the lungs is a significant factor. Not useful to define DR diving, but very useful to consider how long a dive can be and how susceptible a diver might be to low 02 problems. The lungs are a storage area for both 02 and co2. Other things being equal, the more in there, the longer and more comfortable a dive can be and the more reserve available. DR diving involves a tradeoff between maximizing air in the lungs, early onset of DR, and dive efficiency. To illustrate, Eric dives with a much larger lung volume than me. His dives are quite a bit longer than mine, in part (of course, only in part) because of that extra volume. I've played around in the pool with different levels of exhale and it is crystal clear that, on any given day, the comfortable part of the dive is directly related to amount of air in the lungs.

Lets see, going back to the original post.

Most of the merits of FRC should be qualified as coming with practice, and not necessarily quickly.

For me, the primary advantage is longer, much longer, more comfortable dives.
Its real nice to be such a lazy relaxed dive, as well.
Safer dives. This may not be the case for a beginner, hence the numerous warnings to go slow. It assumes that the technique has been reasonably mastered.

I don't get an earlier urge to breath, after, that is, getting used to the technique.

Challenges:

It takes a lot of work to learn. Initial performance suffers.
Depth is reduced. For most divers, practice brings back the moderate depths we usually dive in. However doing serious depth is always limited relative to full lung.


Around to the central question. Is this a technique that could/should be taught to beginners? I think the answer revolves around knowing when to come up. I have never had a problem with that, but my co2 tolerance is so lousy that I may be an exception. What are others experience with this and, particularly, how does that experience relate to how a new diver would experience DR diving?

Connor

 

[Fondueset]

I've only played with this a bit. Now that it's cold here and I am using my frickin' AWESOME 5 mil yamamoto - I am rather bouyant. I dive FRC (by Eric's def) If I am in less than about 10m of water to adjust - sometimes more. In the bahamas when line diving I would experiment pulling myself down the line with various lung volumes. This was primarily to get ready for deeper dives - but it became interesting in and of itself. I would reach a point where I could just hold the line and move very slightly up and down - playing with the sensation in my chest/throat. Its a good way to get a feel for squeeze in a very controlled way. I remember hitting 10m and realizing I had to stop because I'd done a near complete exhale. It would be fun to gradually extend that under the right conditions.

I also do it in the pool - to be neutral or slightly negative in 1m of depth while working out with my monofin without using weight. Its a lot of fun and I've gotten down to two kicks per 25m. (3 arm/kick cycles no fins) without any sort of speedsuit.

By Eric's definition I do a fair amount of FRC at about 85% - its important to keep track of when you are doing it because of the risk of squeeze - I do it when I am not planning a long or particularly deep dive - usually < 25m.

 

[Bill]

'....DR diving starts at any significant amount of exhale below full and stops as exhale approaches empty. Given the variation in divers and styles, its probably not possible to get much closer than that'

Well put Connor.

Last month I met a diver that inhales and packs to over ten liters, exhales 10% and makes an almost unbelievable dive. He called it frc. One of the first divers to shoot fish underwater (with a bow and arrow I believe) used exhale dives before weight belts were available. Different strokes, different folks.

 

[Don Paul]

'....DR diving starts at any significant amount of exhale below full and stops as exhale approaches empty. Given the variation in divers and styles, its probably not possible to get much closer than that'

Well put Connor.

Last month I met a diver that inhales and packs to over ten liters, exhales 10% and makes an almost unbelievable dive. He called it frc. One of the first divers to shoot fish underwater (with a bow and arrow I believe) used exhale dives before weight belts were available. Different strokes, different folks.

The blow and go was a common style with Guy Gilpatric and his Mediterranean buddy's in the 1930's. I have had close calls doing a big partial exhale trying to drop quietly on pelagic game fish 25 years ago in uncontrolled and open sea conditions, which I had no back up plane for.
New divers have much more knowledge to draw from, along with more qualified teachers now. I was very unwise with my choices when I was young.

Cheers, Don Paul

 

[ktreloar]

Hey crew,

good to see such an interest in frc diving, but as said above when first starting frc the important thing to remember is to take very slowly. Do heaps of dives at a comfortable depth where there is no squeezing sensation on the chest. It may only be 10m, but you still need to take it slow. Frc diving conversion can take a while and if rushed, could result in a lung baratruama. As far as volume goes when im in the ocean i do a passive exhale, nothing forced i try not to concentrate on how much i have let out, only just the amount that my chest relaxes. I find by doing this my dives are more consistent then trying to work out how much i have exhaled. Just one more thing Frc results will take time but from what it has yeilded for me is longer more comfortable dives, quicker recoveries and a clearer head on the surface. Just my thoughts guys.

cheers,

Ktreloar

 

[Andrew the fish]

well, may I re-phrase the original question, I think it should read more like

"how to introduce beginners to DR diving in a safe and enjoyable manner"

I am beginner who is practicing FRC diving in a pool for last few days and quite enjoying the process. Honestly, anybody's opinion whether beginners should or should not practice FRC or DR diving will hardly make me change my personal opinion on the subject. I like it, and some other beginner may discover this interesting phenomena for themselves and question really is - "how to", not "wether they should do it at all or not".

My own sensation on the timing, "when to come up" comes as rather hard and unbearable urge to breathe. Feeling in the lungs is that all of a sudden I get suction, rather than contructions, and this negative pressure feeling aggravates the urgency of surfacing. As I am practicing this in a pool with 6ft depths, I think in this set up it is rather safe, surface is right there. It maybe totally differnet animal in open waters with greater depths.

Someone expressed that most beginners who doesn't know how to breathe may fall into FRC category automatically. I agree with that. In my case I learnt full inhale some 30 years ago when playing trumpet, and my music teacher also happened to be an avid freediver and tought me a few trick as well. So, my definition of FRC is somewhat close to that of Azapa The Trouble Maker's , wearing nothing but mask and boxers I sink right from the surface, and that is where my FRC is.

Now, I have experimented with somewhat different diving pattern and I wonder if this one would fall into FRC or DR diving as well. It is a full inhale diving where I would exhale quite a bit of air somewhere in the middle of a dive, when I hit discomfort sensations but not at contractions yet. I discovered that if I exhale almost everything, in a relaxed way, slowly just let it out, I can stay in a comfort zone for quite a bit longer. Not just sit there but move around for quite a bit, like another 30 seconds at least, before I hit another boundary of comfort. If I do not exhale, I would be "blue in the face fighting contractions" at this point. I don't know how would this pattern relate to distance dives or static apnea attempts, to me this is about comfort and pleasure.

 

[Kars]

Hi Andrew,

Thanks for your question, I understand your need for some explanations how to learn FRC diving and gain the most benefit in the shortest time, seeking comfort and (longer) pleasure.

I don't consider myself an FRC freedive expert, though I do have some experience.
For myself I use several approaches, full lung, packing, sub full, FRC(exhale until one sinks in swimming trunks), passive exhale, full exhale.

In my training experiments I focus on finding out the mechanical, psychological etc principles of freediving. To do this I like to compare the different approaches, test ideas, observe and share with our super brain: Deeperblue

It's great you have a very clear dive alarm, something that I missed for years in the beginning of my freediving career. I had a hard time knowing when to surface, resulting in BO's and samba's during competition. I would very much like to find out weather it's easier for a novice to know their limit by diving FRC?
On the comfort question, relaxation, flexibility, mind space, body temperture are some of main contributing factors. Some of my latest observations are the importance of a slow last breath and head position. Mind space, the ability to remain in a state of non judgement, a lucid trance, just witnessing and enjoying the bodily sensations. As with the last pb, the attitude "I dont expect anything, we will see" seems a thought connected with many of my pb's I would be very interested to know how to be able to let myself be in that state of mind. - Any suggestions are welcome. Ambitions seem to be bad for this lucid mindset. Suddenly being put to a test seems to help, as this event seems to excuse oneself from the expectation to be able to perform the best.

I think your slow exhale helps your muscles to relax and to stabilise/lower your CO2 a bit.
There is also a mental component, a sigh of relieve, and a bodily association that comes with a lowering heart rate. Strained muscles use a lot of O2.
In dynamic with monofin I take the turn bringing up my legs as a moment to relax the muscles.

To bring the discussion back to FRC training.

I do think FRC can help to learn and develop students to a higher levels faster.
But I think there should be a base in understanding of the lower level freediving principles. FRC diving introduces another variable that can make surfacing at the right time more difficult. FRC could have people miss out on important freediving techniques such as know how to take a full breath. On the positive side, I think FRC divers will train much more the DR and swimming in the anaerobic part of the dive. FRC divers tend to focus even more on relaxation and find more, even in the anaerobic phase. FRC training appears to be more time efficient too, more time in anaerobic mode, quicker recovery, less swimming distance and dive time needed.

Considering Depth, I think FRC is not well suited for beginners. Beginners already have a difficulty equalising to 10m with full lungs. Diving full lungs they will learn to make a proper duck dive, have good hydrodynamics, learn the effects of buoyancy, have a gradual increase in flexibility, have more margin in their O2 supply, and more.
For now I would say don't deep dive FRC when 20m isn't comfortable on full lungs.
Shallow -5m dives I don't regard as deep diving obviously.

Ok, I should clean up this post as I'm just rambling, but today I'm cold and low on energy. I hope it's still a useful post.

 

[cdavis]

Kars, thanks. It might be a little rambling, but it sure is interesting. I agree on depth, especially if the diver is exhaling to significantly less than 1/2 lung.

Andrew, a little background: Several places in these forums, divers have reported on early and unexpected B0s with little urge to breathe during full or near full exhale statics at modest depth. Further, those of us who have explored DR/FRC diving extensively all find that the body's signals are very different from full lung. Some find it hard to identify when to come up. Put those together and there is substantial caution about the idea of newbies jumping into FRC. Note: you are obviously not a newbie.

Sounds like you, like me, have no problem with when to come up. Maybe your c02 tolerance is as bad as mine. Some folks are different. I dive with a couple of guys who get very little urge to breathe; one doesn't get contractions at all and has had to learn a different set of signals on when to come up. Divers like them might well have difficulty with FRC, and who can tell who they are in advance, hence the advise to go slow.

Your report on exhaling part way through the dive is very interesting. I had not run into that. From a physiological point of view, that should be very inefficient in terms of 02 consumption, and maybe not safe for one with high c02 tolerance. Of course, I'll give it a go next time I hit the pool, very curious.

Connor

 

[Andrew the fish]

you are obviously not a newbie.

I was fond of free diving from my early teens well into 20's. But I never had any formal training or reading on freediving, and none was available back then. Now I am 43 and slowly getting back into freediving, after almost 20 years of enjoying other things. I feel like a newbie, this is much advanced sport these days, with internet and collective brain power that dwarf whatever I know by a lot.