heart rate question

[ChickWithBrains]

Just to reiterate: you're not on meds, right? If you were on a beta-blocker for blood pressure, it prevents reaching your max heart rate as well as lowering pressure.

Don't stress about a stress test; it's unlikely that ischemia (lack of oxygen to your heart because of clogged arteries) are causing this without you getting totally winded or developing chest pain. That's not to say that it may not be something cardiac, but "the big scary one" is sort of unlikely.

When's the last time you had your thyroid checked?

If you haven't already, borrow a friend's HRM and go for a solo ride to MAKE SURE that it's not your monitor and interference with riding buddies!

Max HR with identical effort decreases over time as we age. And as we get fit. It doesn't make sense that your numbers would change dramatically between one day and the next, but you now compared to you 10 years ago would yield different max HR on identical field tests. Just to keep in mind.

[slmdunc]

Something similar happened to me with a heartrate monitor that was on my personal treadmill. All of a sudden, I couldn't go over 115. I didn't get it. I FELT like I was working hard, I was sweating... but it just wouldn't go up. Turns out - it was the monitor. Never worked right again after that. Not sure of the specifics of WHY it broke, or WHAT broke on it... but it wasn't me.

I hope that's what it is for you!