Packing vs. a FULL inhale

[DeepThought]

In a breathhold when do you suppose normally the DR kicks in?

I suppose physiological responses start to happen the second you hold your breath (and some take minutes, like contractions). Also there are some pre-breathold responses that many have due to psychological factors (increased HR for example). IIRC Seb Murat said that the DR starts the second you get in the water.

Is it possible that the body has learned to use packing as a signal that a dive will follow. Psychologically similar, if you will, like a young child's bladder when the car starts to move.

Possible - sure. Likely? no idea. Maybe we should start a survey on HR while packing. From the little I saw, HR increase to 120 and even 200 (maybe a heart monitor mistake) is more common than a drop, but who knows.

 

[Mullins]

The HR monitor I was using had a tendency to read the contraction of each ventricle as a separate beat - so it was sometimes reading 240bpm, which was a bit worrying!

 

[wjohnson100]

Let's try some mathematical theory. Lets say your FVC is about 6 liters with about one liter of residual volume for a total of 7 liters lung capacity. Anatomical dead space about a 100 ccs so lets just ignore that. lets say you pack 1 liter. That is a lot for lungs of 7 liters but lets go for it. That is an addition in air to the lungs of about 14%. Not the whole story though. Your lungs only contain somewhere close to about 50% of the total O2 in your body at the beginning of your hold so an increase of 14% really amounts to about a 7% improvement in O2 inventory. Still not the whole story. Takes time for all that packing. Lets say 10 seconds. 10 seconds on a 6:00 hold is somewhere close to 2.5% so you already lost that much to reduce your packing help to about 4.5% and that is being generous. Still not the whole story though. All that increase of air in the lungs puts a lot of pressure on the heart, unavoidable really. That is why your heart rate shoots up so far at the beginning of any breath hold, especially if you pack. I am estimating about a 3% cost in increased heart rate. That leaves you with less than a 2% benefit from packing. On a 6:00 breath hold that will give you maybe 7 seconds if you are lucky. Enjoy your 7 seconds. And don't forget that on a dive there are negative effects from packing too. Also when packing there is a tendency to think that if a little bit is good then a little more will be better. I will still probably pack on my dives just because I can, but I am not totally convinced that there is any benefit other than a bigger supply of air for equalization.

 

[Mullins]

That's a good way of looking at it. However the numbers can vary quite a bit. For me, FVC=10l and packing=3.5l, which is a 35% volume increase and so a 17.5% O2 increase overall. Packing that much takes 20 seconds at most, which is 4.1% of an 8:00 breathhold, so I'm getting 13.4% benefit before any deductions for increased HR. Take off your estimated 3% for HR and I'm still left with 10.4%, which is about 50 seconds! Some people with 8l FVC and good no-packing performances can pack the same amount, which would make their gains even bigger i.e. >1:00

Edit: I missed RV (1.5l), however the O2 percentage of that airspace is probably rather low so it should probably be halved (.75l) when put into the equation alongside inhaled air. This wouldn't change the final figure a great deal.

Another Edit: FIV is probably quite a bit lower when you're in the water, while FIV+packing would be the same. This would raise the FIV+packing/FIV ratio, but I have no idea by how much.

 

[wjohnson100]

Interesting perspective. My FVC is about 7.5 liters giving me a total lung volume is somewhere in the 8.5-9 liter range. I have done 7 minute holds without packing. One thing you mentioned about residual volume. The O2% in that area depends entirely on how you are breathing. As an example. If you take five 50% breaths about 97% of the air in your lungs including residual volume will be no older than those breaths. So if you are taking 5 purge breaths, your residual capacity is pretty well cleaned up with good air. The numbers get better if you are taking deeper breaths, but of course the deeper you breathe and the harder you work at it, the more the added cost in terms of energy use. For most people who are taking deeper purge breaths the good air goes up to about 99%. Almost impossible to get it much higher than that. In my opinion, that is the benefit of purge breaths. They put to use the residual volume. One aspect that I forgot to mention is this. The cost of packing in terms of O2 is probably higher than the straight percentage because the time you are delaying the start of the hold is during a period of relatively higher metabolism so the O2 depletion in the lungs while you are packing is higher than the average for the entire hold. I have no feel for the numbers. I would love to do the science on this. The only way to do it would be to measure the %O2 in your lungs at the beginning of a hold with and without packing with all other things being the same. I am sure there is equipment that can measure it. Another way to know would be to use a pulse oximeter and see how long it takes to start dropping after you start the hold. It would take alot of repetitions to get reliable data, but it might shed some interesting light on the subject.

 

[azapa]

this is great information. what still bothers me is how to do/define a really good non packed full inhale. Is sounds easy but is not, especialy: in the water through a snorkel (spearfishing scenario) or with the pressure of a weight belt (even though it should be on hips, the thing shifts) and tightness of suit etc. From what wjohnoson is saying, an good breathe up and optimal full inhale and your good to go.

How consistant are full inhales that are not packed (for those that have tried)? 5%+-? Better? It would make sense to take the time to learn a really good full inhale before learning packing.

 

[Mullins]

A couple of quibbles:

If you take five 50% breaths about 97% of the air in your lungs including residual volume will be no older than those breaths. So if you are taking 5 purge breaths, your residual capacity is pretty well cleaned up with good air.

Those 5 breaths take a significant amount of time (20-50s depending on how aggressive your breathup is), during which gas exchange is continuing and the pp02 of the dead airspace would fall significantly. If I remember correctly it's very difficult to get your overall post-inhale alveolar ppO2 up past 18%, so I think the percentage of O2 in RV would be quite low. I'm inclined to stick to my 10% figure but that really is just a guess.

The cost of packing in terms of O2 is probably higher than the straight percentage because the time you are delaying the start of the hold is during a period of relatively higher metabolism so the O2 depletion in the lungs while you are packing is higher than the average for the entire hold.

You will go through this phase of increased O2 consumption at the start of the breathhold regardless of whether you spend that time packing or not, so you're not losing any more than the time it takes to pack (the delay between the inhale and the stopwatch going off). I know there is the question of how much packing increases O2 consumption, but that's already accounted for by your 3% figure.

Simon, I'm interested in that too as I spearfish in a thick (6.5mm) suit and it does seem to restrict my inhale volume quite a lot. That's a good idea for a course actually - compare students' dry vs [wet+wetsuit] inhales. For DYN I often stand up to inhale then sit back down to pack, with only my head above water. The extra effort of an inhale when submerged is very noticeable.

 

[wjohnson100]

Just to clarify my ambiguity, not talking about long time for the 5X50% breaths, only about 5 seconds total, with a stong emphasis on filling the belly and the chest in that order. The emphasis is on the inhale to make sure the whole lung is being filled with each breath. I did a competition in early 2008. Before that I had been doing 3:30/4:00 warmup holds with great effort. I decided to try to reduce the strain of the warmup, a good thing I thought. I did two things, added the purge breaths, and started doing warmup holds to a point well before contractions. Now I am doing about 2:45/3:15/3:45/4:15 as a warmup with relative ease. Sometimes if I feel good I chop it to 2:45/3:30/4:15, all to a final O2 Saturation of 96-97%. After my warmup I am at a point where my O2 Saturation doesn't start to drop significantly in a hold till about 4:15-4:30. I have subsequently gone as far as 6:30 with relative ease and 6:00 with 79% O2 saturation. It seems to be working, but I still have not tried to extend past 6:30. Contractions for me, have always started late I think. At the 6:30 point I have stopped just prior to contractions starting. Remains to be seen if this training method will ultimately work or if I am all wrong about it.

On the subject of full breaths, it is something you just have to practice. I have found that on dry holds I can take in too full a breath. In the water that is not possible I think. Not sure what the ultimate is. When I dive I do about 10 quick packs just to be sure. Not exactly sure what that is in terms of volume, about 600 ccs I think. Don't take advice on me about how to pack though, I am certainly not the expert as my experience in the water is very low. I have never lived in an area where freediving is strong, so I have to travel to train, dive, and compete.

 

[Mullins]

Wow, yeah that's a big difference. 5x50% breaths in 5 seconds would definitely raise the pp02 of those dead air spaces (not to mention venous O2 given the raised HR), but in my case would blow off way too much CO2.

 

[B-J]

Have you ever tried out packing with a snorkel. It is possible but less effective. You only get what you can push down with your tongue. What I`m wondering about now is that if I do that movement backwards I get air from my lungs to my mouth. I`ve tested just a little bit on a frc-dive and it seems like I can get air into my mouth after the point where I can`t do a mouthfill. Any ideas about this?

 

[azapa]

I have seen Eric Fattah's the WR CWT dive video from a few years back and he appears to pack quite heavily through his snorkel. I can't do it though.
B-J, I think what you are talking about is reverse packing, or "the grouper grunt" as it is sometimes know (well, in the "Florida courses" at least). It is very powerful and can take you lungs way below residual volume. If I don't do that I can't EQ past 30m or so (lousy/non-existent mouthfill, have not learn't that bit yet!)

 

[efattah]

Have you ever tried out packing with a snorkel. It is possible but less effective. You only get what you can push down with your tongue. What I`m wondering about now is that if I do that movement backwards I get air from my lungs to my mouth. I`ve tested just a little bit on a frc-dive and it seems like I can get air into my mouth after the point where I can`t do a mouthfill. Any ideas about this?

Reverse packing as a method of equalization has lost popularity. The main reason is that reverse packing won't take you nearly as far as a good mouthfill done at a shallow depth. It is also more energy intensive. At extreme depth you must exhale & contract your diaphragm and then reverse pack.

 

[wjohnson100]

Yea, one way to practice this is to do a full exhale, then practice the technique you mentioned to move more air to your mouth out of an empty lung. It can be done. Not sure how effective at depth. I know on land I can get more than three mouthfills.

 

[wjohnson100]

Wow, yeah that's a big difference. 5x50% breaths in 5 seconds would definitely raise the pp02 of those dead air spaces (not to mention venous O2 given the raised HR), but in my case would blow off way too much CO2.

Yea, that is a true. I think that one reason there is not much published in books about specific breathe up techniques is that individual methods vary so much. The only thing people will say is NEVER Hyperventillate. Problem is that the term "hyperventillation" covers anything that exceeds normal tidal breathing. We are all guilty of that. I used to get dizzy doing 5-6 breaths per minute. People respond by saying NO EXCESSIVE Hyperventillation. Problem is that "excessive" is a very subjective term. I wish the 9 minute and above individuals would do some serious writing on the subject. They have obviously figured all this out.

 

[trux]

... One thing you mentioned about residual volume. The O2% in that area depends entirely on how you are breathing. As an example. If you take five 50% breaths about 97% of the air in your lungs including residual volume will be no older than those breaths. So if you are taking 5 purge breaths, your residual capacity is pretty well cleaned up with good air.

I am sorry, but this is completely wrong and the following calculation is flawed. It is as if you had a water well containing 100 liters of water and thought you could get it completely dry by pulling out 10 buckets of 10 liters from it. In the same way as water continues to flow into the well the faster the more water you pull out (with the gradient of levels between the well and the phreatic water), also CO2 from the body flows into the lungs the more the deeper you breathe. The alveolar partial pressure of CO2 does not change a lot, and is almost pretty constant. You can lower it with serious hyperventilation, when you manage to lower the stock of CO2 in entire body, but normally you rather want to avoid it.

The gas, both O2 and CO2 moves in the lungs thanks to diffusion (with the difference of partial pressures in individual parts), not really with ventilation. Hence, the depth of the breathing plays much smaller role than it looks like. Breathing normally will result in PAO2 (Partial Alveolar pressure) of some 100 mmHg (around 13%), while with extreme hyperventilation you may manage blowing off around 4% of the alveolar CO2 (being still continuously repleted from the body). At moderate hyperventilation, or few purges, the difference in alveolar percentage will be even lower, while the lowering of CO2 in body may be still important.

Now, there are other effects of the purges and hyperventilation, that may (under certain conditions and to some extent) increase the stock of oxygen in your venous blood, but there are also negative effects of the low CO2 - hence when you decide for hyperventilation (and purges are nothing else than that), a very careful balance is needed. This was discussed in depth in other threads about hyperventilation, so I won't repeat it here again.

 

[hteas]

Trux,
As you have mentioned, purges may increase pO2 slightly and will decrease pCO2, throwing off homeostasis.
What about hook breaths? Based on what I learned in a Performance class, the hook breath, by increasing the pressure in the lungs, should increase alveolar pO2 while having little effect on CO2 (since they are short and few repetitions are done). The increased pressure should retain the CO2, but would it increase pO2 enough to be worth the extra effort.
I learned to use them after long dives to maintain elevated blood pressure and keep from getting an LMC or worse. But is there enough pressure gradient increase to provide a benefit?
Howard

 

[Mullins]

I think the idea of hook breaths is to raise blood cerebral pressure as much as to increase ppO2

 

[hteas]

I agree Dave, especially for negatives and FRC (at least for me). I'm just wondering whether there is enough pressure built up to increase the O2 gradient enough to add a little extra O2 before a dive to go along with keeping me out of sambaland afterwards.

 

[wjohnson100]

I am sorry, but this is completely wrong and the following calculation is flawed. It is as if you had a water well containing 100 liters of water and thought you could get it completely dry by pulling out 10 buckets of 10 liters from it. In the same way as water continues to flow into the well the faster the more water you pull out (with the gradient of levels between the well and the phreatic water), also CO2 from the body flows into the lungs the more the deeper you breathe. The alveolar partial pressure of CO2 does not change a lot, and is almost pretty constant. You can lower it with serious hyperventilation, when you manage to lower the stock of CO2 in entire body, but normally you rather want to avoid it.

The gas, both O2 and CO2 moves in the lungs thanks to diffusion (with the difference of partial pressures in individual parts), not really with ventilation. Hence, the depth of the breathing plays much smaller role than it looks like. Breathing normally will result in PAO2 (Partial Alveolar pressure) of some 100 mmHg (around 13%), while with extreme hyperventilation you may manage blowing off around 4% of the alveolar CO2 (being still continuously repleted from the body). At moderate hyperventilation, or few purges, the difference in alveolar percentage will be even lower, while the lowering of CO2 in body may be still important.

Now, there are other effects of the purges and hyperventilation, that may (under certain conditions and to some extent) increase the stock of oxygen in your venous blood, but there are also negative effects of the low CO2 - hence when you decide for hyperventilation (and purges are nothing else than that), a very careful balance is needed. This was discussed in depth in other threads about hyperventilation, so I won't repeat it here again.

Sorry for oversimplifying. I was just trying to give some perspective on the effectiveness of purge breaths as they relate to their ability to dilute the old air in your lungs. To simplify the calculations, I intentionally ignored the other factors, as they are beyond my measurement ability. I get a quick number that is useful, keeping in mind the factors you discussed. I can know, for example, that 5 purge breaths might be effective, 10 is probably a waste of energy, and would also increase the negative effects you mentioned. Just a useful number to keep in mind, one of many we all use.

Hope this clarifies.

Walt

 

[wjohnson100]

One question I had about packing. How do you get past the discomfort. I find it very disconcerting during a static when the discomfort level is so high, and I haven't tried more than about 10 packs. I currently am doing rock solid 6:30 holds without packing and without too much difficulty. I think packing would help take me to the next level, but so far I have not been able to get past the discomfort.