Originally Posted by
wphamilton
I didn't stop the run and check my pulse if that's what you mean, mainly because I wasn't watching it that closely. Actually 200-209, not "over" 209.
It's not unusual to start high and have a sudden drop, but it would normally ramp up first and only to 180's or so. I've never seen one jump up like this which is why I think "mismeasure" or worry about a problem. Objectively it's probably not either.
I often get a high HR over 200 at the start of a ride if my jersey is dry and flapping at all. Once I start to sweat it settles down. If you don't feel anything different when it's up it's likely just a measurement error. Pretty easy to check with your finger on your neck even while running. 200+ is fairly easy to notice. You could also have a condition like Afib but you'd likely feel that.