When I was in my worst flare ever, my resting heart rate was about
160 (this is when I'd wake up in the middle of the night and take it). They sent me to a cardiologist and it got up to 200 walking 4 mph on the treadmill. They did several tests and everything was working fine, so they attributed it to stress. As the flare got better, the heart rate did go down a lot. I still have a higher than normal rate, but it is MUCH better than it was and stays pretty consistent now.