where you run on a treadmill and push yourself, and a chemical - i've never done it, but heard my wife talk about it - they inject you with chemicals to simulate a heavy physical load.. so, they take your BP and vitals before pushing the med through an IV, then push the med and monitor your BP and vitals.. Its supposed to simulate an actual physical stress test.. I would imagine they only do it for people who cannot - at least at the time - do a treadmill test..
Friendship is like peeing your pants.. Everybody can see it, but only you can feel the warmth..