I remember to see a study where they concluded that PVC usually get more frequent when the heart increases, then gets less frequent when it increases even more...
For example, if you have PVCs at 80bpm, you will have more at 100-120bmp but less at 140-150bpm
But that's only the usual pattern, because everyone is different. Some people have them at rest, others when exercising, others after exercising, others in patterns (bigeminy, etc).
For example, in my particular case I used to have them only when resting, but since a few years ago I get lots of them when I exercise, especially if I am anxious.
I am currently running around 14,000 PVC's a day. My BMP are between 65 and 145. I have PVC's no matter what my BMP are.