steroid use is pretty common in the military, in general. the SpecOps guys are operating at such a high tempo, and many are in their 30's, to boot.
EQ and moderate dose testosterone is very common among that crew.... not so much that they blow up, but enough that they're stronger, have more endurance and most importantly: RECOVERY. going without sleep or very little sleep and having to do all that stuff is damn near impossible as one ages...
side note: i'm curious if the military ever did bloodwork on guys finishing up Ranger school, BUDs, Selection, etc... prolly pretty scary to see how suppressed everything would be..
EDIT: i just found this... pretty interesting: http://www.academia.edu/4112946/Physiological_Consequences_of_U.S._Army_Ranger_Training