The best way to do High Intensity Training or Fast Exercise is on an exercise machine like an elliptical trainer, that works both upper and lower body. This way, you don’t have to warm up, or you don’t have to warm up as much. Schwin Airdyne Pro also works both upper and lower body, but it’s not as effeicient because you are seated. You get a far greater bang for your exercise buck, working out on a machine that has you stand. Some steppers and treadmills also work upper body, which is what you want to look for. If you don’t have exercise equipment handy, sprinting is probably your best option.