I had the blackout in July 2019 in Cyprus during a competition. I was going for what is usually an easy dive for me, 100 meter free immersion, and the dive went very well, all the way, on the way down, on the way up and i was fine during the dive. I remember seeing the safety picking me up at 30 meters, at 20 meters, i was still fine and suddenly around 15 meters i completely lost it and i blacked out. Why this happened, it was a bit unclear at the beginning on such a dive, where everything was going well, why would i black out? We inquired and made some blood tests and many other different tests after and we found out i had a big lack of potassium in my blood, caused by an accumulation of lack of potassium over the the six months leading to the blackout. So, actually it was a medical condition, it was not like related to freediving, the blackout was the consequence of this lack of potassium. So now if i had one advice, if you are going for deep dives, is to have you checked regularly on everything, just to make sure you have all the minerals, all of all the nutrients you need for your body and that you are in perfect health before doing like deep deep dives.