I ran into something odd yesterday (for reference it was on my 69th birthday). It was wet and cold so it was an indoor ride on my spinner bike (that has Garmin Vector pedals). I am not really training for anything these days and just ride like I feel. Yesterday started with a slow build from around 80% of ftp up to around 110% of ftp over a 30 minute period. That was enough of that, and the last 30 minutes was at a more casual pace in the 85% to 90% of ftp range.

My HR acted like you would expect in the first 30 minutes building steadily up to around 160 bpm at the end (my max HR is low 170's). After the first 30 minutes I spent a minute or so idly pedaling and finding the jazz guitar feed that I wanted to listen to, and spent the last 30 minutes pretty much in the 85 to 90% range and my HR leveled out at around 145'ish...

...EXCEPT for a short period in the middle where it bumped up to around 170 (in less than 10 seconds) and stayed about there for around 2 minutes before going back to the mid 140's where it belonged. Data is coming from a Garmin HR strap to a Garmin Edge 520. I have looked at it on Golden Cheetah as well as having dumped the data to a .csv file. Normally I would not think a thing about this as I have (on rare occasions) seen some far stranger HR stuff than this (like 240 bpm) that I am convinced is an equipment thing. And I felt totally normal. But this time I was wearing a Fitbit and it also was reading this oddly high HR #. So I am strongly inclined to believe that my data is real this time.

I have a annual physical scheduled in 5 weeks and am trying to decide if I need to address this before then (I have no history of heart issues, BTW). Again I want to emphasize that I felt just fine through the whole thing. Nothing like this has happened recently and I pretty much repeated yesterday's indoor ride today (another wet/cold day) without incident.

Comments here on creating an additional physician visit before my already scheduled appointment that has the purpose of investigating stuff like this?

dave