Floyd Mayweather's training regimen included 30-60 minutes of continuous sparring with fresh partners and running 3-4 times per 24-hour cycle, despite the critical need for sleep.

“But the lore is that he would do-- because nowadays, it's 12, three-minute rounds with a minute in between, used to be 15. But now, neuroscientists stepped in, and it turns out a lot of the deaths were occurring when it was more than 12 rounds. For whatever reason, cut off at 12 really seemed to truncate the deaths. There are other things too. If the dad is apparently a cornerman-- we have someone else here at the podcast who knows more about this than me. RICK RUBIN: That's fascinating. ANDREW HUBERMAN: Yeah. The kid not wanting to disappoint the parent correlated with death. I'll get some of this wrong, and they can come after me. But in any case, this guy who was in Floyd's camp said that he would do 30 to 60 minutes of sparring, bringing in fresh sparring partners with no rest. That he would run three or four times per 24 hour cycle, despite all the critical need for sleep.”