Another voice chiming in on this aspect of the training. Having watched the Discovery channel shows on the Seals a couple of times I now consider myself as practicaly a trained expert on the subject.
My understanding from the show was that the training was intended to weed out anyone who would quit. That’s what they are looking for, guys that will never give up. There probably millions who are stronger, faster, bigger, and whatever else, but if they will quit they are not what the Seals want.
I remember watching the final hours of Hell Week. The instructers had the 25 or so that had made that far standing in knee deep water with the waves breaking up around thier waists and chests. The water was cold and they were obviously tired. One of the instructers said, “They’ll stand there and die before they quit.” I think they called them in then and that was about it for Hell Week.
In his book, The Perfect Storm, Sebastian Junger makes a case for the Air National Guard pararescue jumpers having the toughest training course. I’m not going to type the whole two pages of description here, but it looks insane. Here’s a little squib from a book review for The Rescue Season.