See, the funny thing is that all those things - blood sugar, caloric intake, etc - I shoudl have a handle on by now. I'm an endurance runner who has done a number of marathons and a lot of smaller races. I just don't remembering being so sleepy after doing an intense workout before. I like doing endurance sports because I'm better at endurance than speed, so I tend not to go for high intensity, but rather long duration. This high intensity business is relatively new.