do you mean on a treadmill? If so my dd had one today. You walk at an incline of 10, speed 1.7. Every 3 minutes it will increase in incline & speed until you feel you can't do anymore.
You are hooked up to around 10 different electrodes, they monitor your heart & heartrate during the test. They take a BP reading before while laying down. They do another one standing right after you're done the test and again laying down, then every 2-3 minutes for 5-10 minutes.