https://en.m.wikipedia.org/wiki/Shallow-water_blackout https://en.m.wikipedia.org/wiki/Shallow-water_blackout https://en.m.wikipedia.org/wiki/Freediving_blacko

https://en.m.wikipedia.org/wiki/Shallow-water_blackout https://en.m.wikipedia.org/wiki/Shallow-water_blackout https://en.m.wikipedia.org/wiki/Freediving_blackout#Shallow_water_blackout https://en.m.wikipedia.org/wiki/Freediving_blackout#Shallow_... This phenomenon is well-known, probably more so than Wim Hof. You’d think a ‘learning guru’ would learn about the potential risks of holding ones breath underwater while hyperventilating before attempting it!