I was in an experiment with him for the Radboud University back then. It was kind of like a swim or die moment, almost literally since we had to swim in ice wat

I was in an experiment with him for the Radboud University back then. It was kind of like a swim or die moment, almost literally since we had to swim in ice water. The first two days swimming in ice water were not pleasant. The 4th day we were walking on a mountain with -7 degrees celsius, only shoes and shorts. For me, I got the idea of the breathing on day 2 and really integrated it on day 3 and day 4. I think what also really helped is being in a group who's commited for more than one day. If you happen to live in The Netherlands, I would be willing to train with you for 2 days. I haven't done it seriously for a long time (other than DnB parties, don't ask). Edit: oh wait, it was 4 days (can't edit my parent comment). Memory got the better of me, it was like 5 years ago or something (or 4 or 6, definitely not 8).