I was fortunate a few years ago to participate in a study at Stanford that was looking for correlation between exercise and heart rate disease in older folks. They did a sub-maximal HR recovery test on which I scored very well. The real value of the testing was electrocardiography at rest and during exercise. They also look at the aorta and femoral arteries. They didn't find an plaque (I'm in my mid-60's). The exercise portion was done lying on a padded table with a cycling apparatus that measure power. The researcher could examine my heart both during and immediately following the exercise. If anyone ever gets the opportunity to participate in such a study It's quite an experience.