Garmin HRM reading high

had my garmin HRM dual since Xmas and it’s started to give me some funky readings. Namely reading way high on steady rides (202bpm this evening, and I barely hit 180bpm when I’m going full gas).

Any tips on sorting it out before I contact garmin?

The only things I can think of is that I’ve got it too tight (stop it moving around)/my base layer makes it too tight. Or my base layer material, or the battery is going already which I’m doubtful of. I do wet it most days but didn’t tonight, does that really make a difference considering it still reads off when I’m sweating anyway.


Some jerseys can interfere with HRM’s a quick google brings up these pages:

Troubleshooting your heart rate monitor/strap HR spikes | DC Rainmaker

My Heart Rate Monitor Strap is Reporting Erratic Data | Garmin Support

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I had one that would do that till I got sweaty enough, even wetting it beforehand didn’t work. Ended up throwing it out and going to a Polar H10, which hasn’t missed a beat in the 4 years that I’ve owned it

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I had this problem recently with my garmin dual (albeit I got mine June 2021 so out of warranty). I tried a new battery, changing where I wore it etc and landed up buying myself a new one. Yours is still within warranty so I’d get in touch with garmin.

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Does it all link up the same as the garmin does etc? Literally just a different strap…?

I will contact garmin and go from there then since it’s in warranty


Synthetic jerseys used to interfere with HR readings for me. Stray static electricity I guess?

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Can you borrow another strap from a mate? Chances are it’s the strap, but keep an eye on it in case it is your heart! I had similar and after 2 years of blaming the strap found out I had Atrial Fibrillation which was causing it.

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I have noticed 3 things:

  1. Some types of clothing that can hold a static charge can cause high readings that tend to go away when you start to sweat.
  2. When the battery starts to wear out high readings can occur. I have found the HRM tends to read about 2x the normal heart rate at times when this happens.
  3. I have had the sensor pads lifts and start to give erratic readings.

Thanks! I’ve washed the strap, removed and put back the sensor.

I’ll wear it on my commute tonight with a looser, cotton t shirt or cycling jersey and see how it goes. Oh and I’ll really wet it and see if that affects it.

After that I’ll get in touch with garmin - I don’t think the battery should be out after 3-4 months?

It can vary, I have the simpler one (HRM Run) and I’ve replaced the battery maybe four times over 5 years.

Do you have the stock battery that came with the monitor? That may not last as long. I have had varying luck with HR batteries. One challenge historically has been o-ring problems when changing out batteries. I actually track all this stuff. Until recently I have used the Garmin HRM-Tri. The longest I have had a battery last is 140 hours (note this is the actual exercise time and not the total time with the monitor being worn) The last stock battery I had lasted 70 total hours, but i had one that lasted 45 hours. The Garmin HRM-Pro+ is the newest version and does not require any tools to replace the battery. For the older monitors, if the o-ring comes off, you need to make sure it goes back on without any twists. With twists, it will not make a good seal and the battery will not last and the monitor can be degraded by water ingress as well.


Same, except for your #3, and I’ll edit/reorder the list to make my own and keep your #3 as #4.

  1. Some types of weather and clothing can cause low or high readings that tend to go away when you start to sweat. To avoid this I use a dab of Parker Spectra 360 electrode gel, which I learned about from a really old DCRainmaker post. An 8oz tube is cheap and lasts forever.

  2. To avoid build up of body salts on the strap, you need to rinse the strap after every use. And wash after every 8-10 uses. At some point in the future, the strap will need to be replaced. I’m averaging about 3 years before replacing the strap. I’ve seen both too low and too high HR readings when this happens. I’m usually wearing an Apple Watch and can quickly start a workout and compare wrist HR to chest readings.

  3. When the battery starts to run low, you can see erratic readings. I’ve seen both too low and too high HR readings when this happens. I’m usually wearing an Apple Watch and can quickly start a workout and compare wrist HR to chest readings.

  4. The sensor pads can lift and start to give erratic readings. Personally I’ve never had this happen.

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With respect to item 4, I’ve had lifted pads on two monitors. This photo is of the monitor Garmin replaced last week as it was still under warranty.

For #1, I forgot to mention I also have a tube of conductive lube that I sometimes use.

The photo below is my HR on the last run with my old strap. Note The first 10 minutes of this workout were very easy and HR should have been in the 115 to 125 range.


Anagel 250ml Ultrasound Transmission Gel - Pack of 2

Something like this?

Do you have another strap or device to crosscheck with ?
I started getting high HR numbers and found a health issue had snuck up on me at 52
when your A1c gets into the double digits ( like 12+ ) life gets interesting.