I think about 8 of 9 days with no sleep can be fatal for some people, I heard.
While sleep deprivation is part of the training they do get to sleep 3-4 hours daily. They get two MRE’s a day which equal over 2,00 calories but rigorous training eats those calories up. You’ll lose a considerable amount of weight. By the time you get your patch you’ll look like death warmed over.