Heart rate behavior; something to be concerned about?
 

Last week while visiting the in-laws, I went out for a MTB ride to the top of the local mountain (Montara Mtn near Montara/Pacifica, CA). It's a nice ride, and was otherwise uneventful (~1700ft climb on dirt/abandoned pavement, most at ~5% grade, but then it kicks up and flirts with ~25% for very short stretches, which is a challenge to keep from falling off the back of the bike).

The descent lasted ~18min, probably turned the cranks a dozen times, and my heart rate was ~40% MHR. Then pedaled for ~7min with a ~65% MHR on flat/slightly hilly road until the very very short (~90sec) but 20% grade up their street. My Garmin says my heart rate topped out at ~85%. 20sec from the peak HR I stopped (and stopped the Garmin), and my HR was at 67% at that instant. Over the next 2-3 minutes my HR dropped to 20-25% MHR (what I'd usually have sitting quietly), the beats felt very very strong, and it would very noticeably skip a beat (felt like half a beat) every 4 or 5 beats. After ~5min more of standing, the heart rate had risen to ~40% MHR which felt much more natural.

Normally I'd do a reasonably cool down before coming to a complete stop, but I was only thinking about making it to the top of the driveway. I would expect weird things to happen when making such an abrupt change (and I'll avoid doing it in the future), but are the results something to worry about? I'm in my early 40s.

Sounds like an arrhythmia. I would have it checked out. You might need to have a stress test to make it show up.

A number of years ago, when I was in really top shape, I noticed that my resting heart would skip beats, maybe every 5th beat, just like that. I talked to a heart doc, was fitted with a Halter device, but it didn't show anything of medical interest. That's something that can be done, but then you have to try to duplicate the effect during the 24 hours you wear the device.

I guess there were two things that I was interested in, first that the heart rate plummeted immediately after ceasing the exercise and then slowly rose back to where I'd expect it to be, and second the skipping.

Thinking about some televised sports (swimming, track and field, sprint at the end of a road race), at least the winners do all-out efforts and then come to a complete stop without doing any obvious cool down. I've always heard about cooling down to help with lactate acid flushing, etc., so could imagine it really only be helpful, but not required ... but can doing so be injurious to the heart? Is coming to a complete stop really really bad, or is the heart just doing its thing the best it can? The lowest I've ever seen my heart rate [while awake] was 33bpm (~17%) and that took a lot of relaxing and shallow breathing, so to see it hit 20% (~39bpm) on the computer, and feel that it was actually going that slow, while standing and still breathing heavily, was alarming.

I'd be, if not alarmed, certainly concerned enough to get myself checked out. Having your HR drop to resting levels at the top of a hill is not normal. I don't know enough to speculate beyond that.

It's generally not a great idea to stop suddenly as your blood pressure can drop and fainting can occur. I haven't heard of HR dropping so much though. See a doc and get tested would be my recommendation.

I could also be you HRM.

My Polar FT1 sometimes reads in the 230s when I'm stopped and sometimes drops to the low 30s when I'm in my normal training rage of 132-136.

It's also dropped to 00-05 for several minutes on the road and, then, jumped to the 190s.

Na, this was real. I have lots of experience with bogus HR readings, especially on my Polar.

I suspect the drop is easily repeatable, though I was hoping others had experience with it. ~10 years ago I did do a stress test as a part of a comprehensive physical (there wasn't any reason to do it otherwise), and I remember the cardiologist did note there was something [an arrhythmia I assume], but said it was not uncommon and not to be concerned about. I'll get this checked out though.