hi marko
the following is my personal account and i´m NOT suggesting that what i do is right or recommended!
i started freediving sort of more seriously last year, went to thailand earlier this year for 3 months and just spent 1 month at the read sea doing pretty much only that. this to show you i´m not a professional in the sport. so here goes...
part of my training is doing statics and in order to gain some experience and find out what works for me. i try all sorts of breathups to figure out what works. trial and error, you might say.
my first blackout happened a few weeks ago and i had more after that. they all are on land, i never push things in water!, and there is usually somebody around.
my BO´s occur after either excessive hyperventilation or heavy packing before holding my breath. i get dizzy almost immediately, have a tingly sensation and my field of vision shrinks till it seems i look through a straw. this it seems is pretty much the edge. at that level i decide to either go for it hoping that concentration and muscletensing to generate co2 quickly will keep me conscious, or i abort immediately.
i found out that it´s a fine line here. and a few times i went too far. the BO itself i didn´t realise of course. only when i sort of came to me again i noticed i wasn´t holding my breath anymore but breathing very gently. checking my watch i realised i was missing up to 10 seconds. no memory.
a few days ago i tried some heavy packing after mild hyperventilation and immediately lost it. i remember partly that i tried to brace myself on the table (i was sitting on a chair) but my arms weren´t working properly (loss of motor control) and so i fell off my chair. no damage done fortunately.
this incident is probably what everybody refers to as a samba.
about starting breathing after a BO: yes you do. i am not aware of situations where somebody didn´t start breathing automatically after a BO.
of course once in the water there´s a completely new situation. given a SWB you would just hope that you don´t start breathing subconsciously while underwater but after your buddy has taken you up. from what i read so far in water you start breathing within 10-20 seconds, on land within 10 seconds or so.
this in particular would be of some special interest to me and maybe somebody else has some more information regarding that.
i´d slao like some more information about different kinds of BO´s. in my cases i certainly didn´t have lack of o2. or maybe in the `chair incident` because of the pressure generated after packing????
i hope there will be a lot of posts to this topic since improving safety when freediving is certainly one way of having everyone enjoy it even more. especially newcomers like myself. and it seems there are quite alot of us out there. wicked!
cheers
roland