It's also a common misconception that adrenaline,reduces pain responce, studies have shown that it can both marginaly increase and reduce pain response dependent on the typE of pain, the Definning factor in reduced pain response is not adrenaline but the subject being distracted, by what ever is Stressing them, not the bodies reaction to that stress, if you make make them concentrate on the pain, then the pain response is higher, not lower, Ie if it's the pain that is causing the adrenaline release then the pain response will be greater