[Stavros]

Hi Alex,
what is happening to you is that basically as you pack your lungs expand backwards and start pushing your heart and arteries therefore constricting blood circulation to the brain... if you push it to fast too soon you will most likely have an ischemic blackout (ie a black out due to reduced blood circulation to the brain).

So as not to scare you I should mention that this is not as bad as it sounds IF it happens while you are laying down somewhere nice and comfortable (ie laying on you couch or similar) - so as not to hurt yourself when you loose consciousness...
(after such a BO you will wake up after a few seconds when you exhale and pressure in your lungs is released)
If you are standing up - on a hard surface - or in water such a black out might cause injury or even worse especially if you are alone when it happens.

How to avoid these feelings during packing and how to avoid a packing Blackout:

Never pack to the max (depending on your feeling on the day - it might vary from day to day)
Increase your packing volume gradually - like every type of exercise you need to increase things gradually in order to give your body time to adapt.
Practise ribcage stretches which will improve your flexibility and therefore allow your lungs to facilitate more volume.
Pack slowly so your lungs-ribcage-heart have time to adapt.
Never train alone (universal freediving principle)


Have fun
Stavros