72 right now.
I used to be able to make my heart rate drop below 30bmp for about a minute at a time. I remember driving the recovery room nurse crazy after my knee surgery when I was still in high school. It's alot easier to do when you have some audio or visual feedback like a heart rate monitor. I haven't practiced varying my heart rate for years now, and right now when I try I can only get it to fluctuate a little and only for ten seconds or so.