Reverse packing just before a dive?

[FreeRestriction]

Any benefit from reverse packing to totally get a fresh breath for the dive? As in exhale, reverse pack, full inhale, and then dive.

 

[hteas]

The only problem i know if is that it's more difficult to get the next breath when you inhale. I can feel the extra pressure whenever I try it in the pool. I'm too lazy to waste my energy doing it while spearfishing.

 

[Apneaddict]

I do it out of habit.

 

[Simos]

Any benefit from reverse packing to totally get a fresh breath for the dive? As in exhale, reverse pack, full inhale, and then dive.

A couple of deep breaths should refresh the air in your lungs I would guess. Also by the time you reverse pack you'd have used a bit of oxygen and if you then have to pack too it makes for a long time without breathing before you even left the surface.

Even if it helped a bit I think the impractality of it wouldn't help for real world diving

 

[Apneaddict]

I agree. I do 2 or 3 before inhaling for max dynamics.... But it's not needed.

Just a habit.

 

[FreeRestriction]

I see. I suppose there may be a happy medium where your not doing it too long so as to be on empty lungs too long burning up your oxygen reserves waiting just to get a semi fresher breath. So perhaps like apneaddict does 2-3 reverse packs isnt doing anything to hurt your breath hold but if anything maybe a minor benefit.

 

[azapa]

the tendency in 90% of divers (myself included, unless I really take care) is to unconsciously over-breathe before a dive. Hidden hyperventilation, if you like. The small amount of "stale" air in your residual volume will probably contain enough CO2 to compensate a tiny bit. If you think about it, it would only be as stale as the last inhale, as it constantly mixes with fresh air.

 

[FreeRestriction]

the tendency in 90% of divers (myself included, unless I really take care) is to unconsciously over-breathe before a dive. Hidden hyperventilation, if you like. The small amount of "stale" air in your residual volume will probably contain enough CO2 to compensate a tiny bit. If you think about it, it would only be as stale as the last inhale, as it constantly mixes with fresh air.

Are you saying that the left over air in your lungs is as O2 rich/CO2 lean as the air in the atmosphere?

 

[azapa]

I am guessing here, but a small part, the very top, the top of the cones of your lung will have very dead air. I remember Martin Stepanek telling me that weeks after a camping trip when he reverse packed he could taste smoke from the camp fire they had there.

The rest of the RV should mix on every inhale, being only one breath lower on O2 that incoming air, about 14% O2 rather than 21, on average.

 

[trux]

Are you saying that the left over air in your lungs is as O2 rich/CO2 lean as the air in the atmosphere?

Not exactly but close, due to the diffusion. And the level of CO2 in lungs stays pretty stable too. If you do a purge, the CO2 is very quickly replaced by the diffusion from the blood, so it comes back to almost the same level as before. You need to repeat the over-ventilation to sink the CO2 level also in the blood, allowing so a lower level of CO2 in lungs, and hence slightly higher O2 level, but it is then already serious hyperventilation with all its very negative consequences.

The worst is that the reverse packing is slow, so the CO2 level get equalized more than at a rapid purge, so in fact the reverse packing as a purge may have rather the opposite effect than you are looking for, and may not help getting any extra O2 into the lungs at all.

With 2-3 reverse packs you probably do not purge more than some 200ml of air (and possibly even much less if you are not really efficient). And even if you reverse-packed half a liter of air, the gain would be very negligible. The air in lungs in rest contains around 5% of CO2 (and may be lower if you already hyperventilated). So if you replace an extra 500 ml of air (which is unlikely), you remove 500*0.05 = 25ml of CO2. Let's say it is completely replaced by air (which is not true, because the CO2 continuously diffuses back to the lungs). The content of O2 in inhaled air is ~20% (less than in open air due to the increased humidity). It means you get extra 25*0.20 = 25/5 = 5ml of O2. In reality, due to the continuous diffusion, it will be probably rather somewhere below 1ml. I do not think it is really worth of it.

 

[FreeRestriction]

Not exactly but close, due to the diffusion. And the level of CO2 in lungs stays pretty stable too. If you do a purge, the CO2 is very quickly replaced by the diffusion from the blood, so it comes back to almost the same level as before. You need to repeat the over-ventilation to sink the CO2 level also in the blood, allowing so a lower level of CO2 in lungs, and hence slightly higher O2 level, but it is then already serious hyperventilation with all its very negative consequences.

The worst is that the reverse packing is slow, so the CO2 level get equalized more than at a rapid purge, so in fact the reverse packing as a purge may have rather the opposite effect than you are looking for, and may not help getting any extra O2 into the lungs at all.

With 2-3 reverse packs you probably do not purge more than some 200ml of air (and possibly even much less if you are not really efficient). And even if you reverse-packed half a liter of air, the gain would be very negligible. The air in lungs in rest contains around 5% of CO2 (and may be lower if you already hyperventilated). So if you replace an extra 500 ml of air (which is unlikely), you remove 500*0.05 = 25ml of CO2. Let's say it is completely replaced by air (which is not true, because the CO2 continuously diffuses back to the lungs). The content of O2 in inhaled air is ~20% (less than in open air due to the increased humidity). It means you get extra 25*0.20 = 25/5 = 5ml of O2. In reality, due to the continuous diffusion, it will be probably rather somewhere below 1ml. I do not think it is really worth of it.

Oh wow ok great info. I like simplicity so not needing to reverse packs good news.

 

[EARL1220i]

NO REVERSE PACKING thats it hehehehe

 

[azapa]

reverse packing is an interesting tool for freedivers, but not as part of a breathe-up.

 

[efattah]

Reverse packing before the final breath would make things worse.

Breathing is a major myth in freediving. There is a concept that you need to learn to breathe deeply and effectively. Not true. In fact, the most effective breathe-up I have ever found is 'sub neutral' breathing, extremely gentle and extremely shallow, tiny inhale, tiny exhale. It takes a few more breaths to accomplish the same thing, but taking deep inhales or deep exhales just wastes muscular energy and creates an energy deficit before the start of the apnea. Easily demonstrated with a transcutaneous monitor.

 

[FreeRestriction]

Reverse packing before the final breath would make things worse.

Breathing is a major myth in freediving. There is a concept that you need to learn to breathe deeply and effectively. Not true. In fact, the most effective breathe-up I have ever found is 'sub neutral' breathing, extremely gentle and extremely shallow, tiny inhale, tiny exhale. It takes a few more breaths to accomplish the same thing, but taking deep inhales or deep exhales just wastes muscular energy and creates an energy deficit before the start of the apnea. Easily demonstrated with a transcutaneous monitor.

Now when you say tiny inhales and exhales is that a fast, sharp clearing breath or just normal breaths?

 

[trux]

Normal flat shallow breathing as if you sat in front of your TV set, with as little muscular effort as possible

 

[FreeRestriction]

So bassically the best breath up is dont do one then. Interesting.

 

[Siku]

Except a full exhale and a full inhale.

Unless, Trux, your argument re unpacking applies to exhaling also?

And then, if diving FRC, ther's no need for an inhale either!

So we could be left with just - stop breathing and go!?

 

[trux]

Unless, Trux, your argument re unpacking applies to exhaling also?

More or less. The direct O2 gain is rather minimal, and as Eric wrote, the loss due to the muscular effort may be in fact bigger.

 

[baiyoke]

Simple and easy... i like....