Skipping The Warm Up

I don't want my heart rate elevated initially by the FIRST hard race efforts; I want to feel that "heart jumping out of the chest feeling" well before the gun goes off. And in order to do that, without shocking the muscles, a proper warm up is a huge advantage! we warm up for intervals, but then let pre-race jitters throw our warm up off, and still try to GAS it from the gun. Ouch!