I've had anxiety as long as I remember, and it wasn't until last year that I started getting Tachycardia. My heartrate went wicked fast just by going to the washroom and they ran every test and couldn't figure out what was wrong. Over the year I gradually was able to start doing more and more, although my heartrate is still too high when doing physical activity to be comfortable. I've started taking a beta blocker called Propranolol which helps soo much. I haven't had any side effects and feel like I'm finally "normal" again. If the doctor reccommends it, you should try it!