If your friend is worried about accelerated heart rate they can talk to their doctor about taking a beta blocker. I take one when I feel like I'm going to be in a situation that might make me panic. It keeps your heart rate from accelerating. I totally get being afraid of rapid heart rate, it feels like you're going to die when it happens. I could see this from scaring someone out of exercising. I have gotten the rapid heart rate problem from both panic attacks and because I have WPW syndrome (which effects my heart) and causes tachycardia. Very scary. Sorry to anyone who has to deal with, and live in fear of it.

bern929, mine is called: Metoprolol ER Succinate. I don't take it everyday. I only take it an hour before I feel like I'm going to do something that might cause a panic attack (which for me also causes a rapid heart rate.) I might still get a panic attack if I take it, but it will make it so my heart rate doesn't accelerate. Which for me is the scariest part of a panic attack, so it has been really good for me. I've had a prescription for it for about 5 months and only have to take it a few times a week.