I hain't no doc, thats fer shore :) I am a plowboy...Your heart rate drops very fast when you stop exercise. The better shape you're in the faster it drops. Did you check your BP and pulse rate about 30 minutes after you stopped? That is an excellent BP you have and yes your lisinopril (ace inhibitor for hypertension) may have kept it down a bit. I wouldn't worry about that at all. You are trying to get your pulse rate up and sustain it for a period of time (aerobic exercise).
I take beta blockers which limit how fast my heart can beat, and it also limits the force of contraction. My target heart rate for the last stress test I had was 145 bpm and I made it. There is a formula that docs, jocks and fitness freaks use to determine your, or their "target heart rate".
This is an interesting subject to me, that is, what happens to your BP when you exercise.
Aerobic (running,etc) and anaerobic exercise (weight lifting, etc) effects the BP differently. Here is a blurb or two, with some links that might work :) (they call aerobic= dynamic, and anaerobic= static)
"What happens to my blood pressure during exercise?
Although blood pressure goes up during any kind of exercise, the exact changes are different according to whether the exercise is static or dynamic.
Static (or isometric) exercise is defined as a sustained contraction of a muscle group, and is typified by weight lifting.
Dynamic exercise is characterized by intermittent and rhythmical contractions; examples are running, bicycling, and swimming.
During static exercise there is a marked increase of both systolic and diastolic pressure (up to 300/150 mm Hg in champion barbell lifters), whereas with dynamic exercise only the systolic pressure increases.
Many activities involve a mixture of both types of exercise. Using a Nautilus machine produces the same changes as dynamic exercise."