The only way to improve your cardio is with cardio training. I know it sounds redundant, but that's the way I was trained. you have to push your body to the max and then push some more. I usually do a work out in the Hung Gar style and then, when I'm tired, i go into Krav. It is very tiring but I get a little better each time i do this. Give it a try. Push ups, sit-ups jumping jacks, runnning in place, then KRAV!
He who hesitates, meditates...in a horizontal position.