Apr. 6th 2020

First of all, what is packing?
Packing, technically called glossopharyngeal pulmonary autoinsufflation (sounds a bit like - and probably is to an extent - autoerotic asphyxiation, doesn't it? 🤣), is a technique whereby a freediver, after having taken a full inhale, "packs" more air into their lungs.
This is usually done with the nose closed by a noseclip (some do it just with the seal of a mask) and by taking small or bigger gulps of air and forcing it down by sort of a swallowing manoevre (making sure to not actually swallow it, because in the stomach it won't really help us equalize).

The rational behind why it is done is twofold, one probably being less common than the other. The first is that a few "packs" can help bring the lung volume in the water to an equal volume as you'd be able to fill it up to on dry land. Meaning that wearing a suit and being in the water hinders a freediver from being able to take a full inhale, so a few packs counterbalance that negative effect.
The other being that the extra air we pack into our lungs means we can feel more comfortable with pressure, fill up our last time deeper and hence reach a greater depth or have a longer dive when doing a dynamic performance (which I'm guessing you realize is the most common reason why people do it).

So let's see what are the risks, if we really need it and if not, what could we do instead.

Risks

• First of all, packing on dry land is extremely dangerous because - since you don't have the added pressure of the water - you are increasing the pressure in your lungs to such a great extent that the air might actually perfuse into your bloodstream and you might get an embolism, akin to DCS, this was verified by a diving doctor at NASA at one of our recent live sessions. So be very careful and don't even try it outside the water.
• Packing is done after you have taken your last full breath, so now you have in essence begun your breath hold but you are just sitting there and not diving, hence you have a prolonged apnea in total.
• It ruins your relaxation, maybe not mentally if you're used to it, but physically. The norm now before the dive is to breathe while you're sleeping, so you see how after this and a relaxed good full inhale, packing might stress your body and throw off that calm balance.
• More air means you float more, which will make those crucial first few meters of descent that much harder.
• It compresses the heart and may lead to hypotension which means you might black out before you even start your dive. It also stretches the lungs "too much", with whatever possible negative long-term effects that may have on lung elasticity.
• There is very little research to back its efficacy so far. Here is one paper I found though.

Do we need it?

For 99,99% of freedivers out there, I think the answer is a resounding no. There are far better things we could be doing (see below).
Now, for the 0,01% that dive really deep (meaning more than 100m), it might be a trend that helps them get deeper.
But for the sake of argument, humor me in this.
Umberto Pelizzari and others have gone to great depths without packing (and with bifins) - Andrea Zuccari personally told me the other day he did -165m no limits without packing for instance, do you really think that newer athletes with their much better training regimes, excellent supplements, monofins, perfectly gliding wetsuits really need packing to achieve similar or slight greater performances?
Does Alexey Molchanov, argually the best freediver of our times, really "need" packing to achieve the depths he does? Or is it due to his many years of arduous training, discipline, patience and technique as a diver?

What we chould do instead

The facts about the negative effects are just that, facts. The rest is opinion. So, my opinion is that we can and should be focusing on other things to gain a competitive edge and not rely on a trend and shortcut.
Can we really take as full an inhale as we are able to? Can we do it in a calm controlled manner?
Is our technique so perfect already that we shouldn't focus on it more?
Are our equalization skills honed to absolute perfection and we still can't dive as deep as we want?
Is our CO2 tolerance, flexibility and fitness perfect?
So, you see that there are many aspects of freediving that we should be working on - each can take years to "perfect" - and aspects that will not only make us better, more consistent and elegant freedivers, they will make us better, stronger, calmer people.

After all, freediving is an activity for a lifetime, what's the use of cramming as much as possible in there? Enjoy the journey.