"Josh Waitzkin: The 30-second version is that I was doing some Wim Hof-inspired breath hold work. I made the mistake of doing it during lots of reps of underwater swims, 50-meter swims, at a pool in New York City. And on my eighth or 10th rep, I blacked out in a bliss state and I spent four minutes in the bottom of the pool after blacking out from oxygen deprivation. This old guy pulled me out and, which I’m eternally grateful for, and I basically drowned. All the doctors said after 45 to 60 seconds I should have been brain dead or dead, but it was four minutes on the bottom of the pool and that my training saved me. Also, you could say, put me there—but that’s a whole other conversation!"
[0] https://tim.blog/2020/03/14/josh-waitzkin-transcript-412/