Stripped to the waist, and I’m a woman, so it’s a little more significant than with a guy. I had to perform an EKG on myself for certification for a study, and the instructions specified that a woman patient’s bra had to be removed. Not only did I lock the door, I put up a “do not disturb, testing in progress” sign.
To be precise, the performance of the EKG was what I was being certified on, not the results - they wanted to know I could perform one, rather than being concerned about whether I had a normal EKG. 
(And I did!)