Here be a nifty Wired article on some projects for getting more out of their soldiers. No super-soldier serum (sorry RB) but some very interesting stuff about using hydrogen sulphide to suspend animation in critically-injured cases (applicable way more off the battlefield: give a first-responder motorbike a tank of the stuff!), and fascinating heat-transfer gear that can get your core up (or down) to temperature fast. This chimes with the way I always use my hands as heatsinks but the extent to which it worked was awesome. Stick a Glove in every lifeboat!