Did you feel 'normal' or did you feel your increased heart beat? Could you feel your heart pounding? Just checking with regards to a very improbable case of tachycardia.

Honestly, the more I look at the HR, the more I think it's a Garmin-modelled curve. It looks like one from a watch. The more I look at the HRV, it looks like your device wasn't working, like a connection interference of sorts.

No, no heart pounding, no "effort". Really just a well paced recovery run that felt like one. I actually switched from wrist to strap some time ago because I figured it must have been a wrist HR problem since I didn't feel my HR actually going up. But the issue is there also with the strap.

I got one example out, but I'd say 60% of my runs have no weird peak, and 40% of my runs have the weird peak (and associated weird HRV). The only interference I can think of are my BT headphones - but again... I get the weird peak as well when I don't run with headphones.

I could only recommend making sure the sensors are slightly wet before putting around your chest and then doing some tests:

• Try running steady pace on a treadmill, topless
• Give your HRM belt to somebody else to run
• Try somebody's else HRM (assuming you don't want to buy another belt)

It's pretty common to have issues like that with chest straps when it's cool and dry outside during the first 10 minutes of the run. Dry skin + low sweat rate, and technical fabrics can result in static interference. That's the way I would lean, except for your report of similar issues with optical heart rates...OHR is not affected by the same phenomenon. But, ohr can cadence lock which can also have the same characteristic.

Do you have any prior cardiac medical history? If so, then I would call your doctor and discuss.

If you're young with no prior history, I'd try using electrode gel on the chest strap contacts, and see if the issue goes away. If not, again, call your doctor.

What is the brand and model of your chest strap?

Garmin straps suck. I've been through..... Soooo many garmin straps (4x hrm-tri, 3x hard straps, 2x hrm-run, 1x hrm-pro) . I really don't know why.... But, I have had no ends of trouble with faulty readings from garmin straps...very similar to what you show.

I'm

I've heard good things about this -
https://www.amazon.com/dp/B07R8741CN?psc=1&ref=ppx_yo2ov_dt_b_product_details

Don't know anything about it.

I have switched to a wahoo tikr, it's been solid for about 6 months. Which is 5 months longer than most of those garmin straps I listed.

https://www.youtube.com/watch?v=KH1aOiGX_j0

Sorry. That video tells me nothing. And I don't know him from Adam...and, I don't trust random dudes on the internet who simply say, "I put it on and it beeps and it's 30% cheaper."

I spent months Troubleshooting my garmin straps... Dc rainmaker style. I wore multiple watches, multiple straps and downloaded simultaneous fit files to compare and cross-check them. I borrowed polar straps, bought the wahoo strap, and multiple optical straps from different vendors. I used my old 920xt, my new fenix 6, and my edge130 cycling head unit to record data simultaneously from different combinations of all these. I tried various workouts running and cycling. I uploaded all kinds of data to garmin. They send me at least 4 different replacement straps based on my uploaded data showing they were faulty.

Wahoo and polar both worked fine. Garmin was a disaster after a month every time. About the only person I trust for athletic tech is dc rainmaker or gplama. It's just too much of a pain in the ass to have faulty hr data.

Maybe that thing is fine. Can't tell. But, I wouldn't buy it based on that video alone.

well known issue with chest straps. they brush over the "technical shirt" screwing up the sensor. as you sweat it fixes itself.
solution is to get the strap wet on the outside at the area where the contacts are.

Lately...start running, warm-up speed. HR goes to 150 bpm while cruising. Stop. Douse HR strap with water from bottle while walking back to the start. Start #2. HR perfect. Frustrating. But consistent!

It happens topless on TM as well. I also have a Scosche Rhythm+ (arm HR) and I get the same issue, though I haven't used the Scosche in ages.

I never get the issue on the bike. Only while running.

Manually check to see if it's correct. When the heart rate monitor is reading extra high then stop and feel your pulse with a stopwatch and count it.

If you feel exactly the same when your HRM is reading two different levels then it could just be a technology problem. If you feel different when the heart rate is reading high, such as short of breath, weakness, heart pounding/skipping/racing, then you'd want to rule out arrhythmias. Talk with your doc.