Garmin / Wahoo keeps picking up other people's HR monitors

During the last 2 races I’ve done my device, one race with a Garmin 520 and now a Wahoo Bolt, I look down at my device and my heart rate reading is bonkers. It’s not mine. My device will, for some reason, pick up somebody else HR strap. I max out at 180 and in the last race it was reading 221. It will go back to my HR strap once I am far enough away from the other person but until then my readings are crazy.

The garmin HR strap is connected via bluetooth in both instances, which I thought they said in a podcast that BT is more stable and reliable than ANT.

In the last race the strap was connected to the device 5 miles before the race started, as I rode there. Never stopped the ride, never turned it off, kept the device running on the same ride until I got back home.
But at some point, during the group lineup, it started grabbing another person’s HR strap.
Seems strange that after you go through the whole pairing procedure it just picks up another strap willy nilly.


Anything above the grey line is over 200. That’s not my heart.

Garmin 520 only supports ANT+. I’m guessing your chest strap is older and not working well. Do you have another strap to try?

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How do you know that its picking up someone elses hrm? Does it say on the garmin screen that its been paired with another device?

Is it possible that you have a slightly older soft strap HRM and it takes some sweat to get it working well? I had a few instances where my HRM would ready crazy (often very high) until I was sweating enough. I attributed it to colder and drier seasons where static from my shirt caused the thing to do nuts.

I struggled with electrode gel, wetting my shirt, wetting the strap, but never really felt like I truly nailed the answer - wetting shirt and strap maybe most consistently “good” results.

I have a newer garmin HRM TRI and haven’t seen the issue yet, but will say the older early HRM SS and perhaps even TICKRs from Wahoo seem to give me grief. Maybe it took a bit of dried sweat (extra salts?) in the strap before it really was evident.

Sorry if this is all useless but the issue seems odd - once paired it really shouldn’t just jump to BLE device. If your issue is with multiple head units maybe it’s something about the strap itself?

I guess you said BT, so… it must be the Garmin HRM Dual? I would have assumed my statements above had been resolved by the time they introduced that model… Oh well, my two cents.

My HR does not go up to 200. That’s the only way I know.

Having a hrm misread isnt the same as it picking up other signals.

How do you know that your max hr isnt 200?

Sometimes when it’s cold it can have an issue, especially if I don’t wet it before I head out. In both races it was wet and I was warmed up so there was probably some sweat in there as well. When it’s dry and cold and there is no sweat it always reads low, never high.

The monitor is 3-4 years old.
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I’m wondering if I change the name of the device to something more unique it will stop grabbing other people’s with possibly the same generic name.

I thought it was BT but I must be wrong. I vaguely remember that shortly after I got it I had to get another one to work directly with my phone and trainer independent of the head unit.

Well. I can’t say for sure because there is no way of testing if these monitors are working correctly but I’ve been wearing a HR monitor for years and have never seen anything near 190. I have used 3 different HR monitors (garmin, whoop and a kinetic branded one, which I think might be a wahoo) and they all have my peak around 180. Aside from the whoop, in a couple cases, but that’s another story.

I just know it’s not 200+ based on the data from years of wearing a strap. If anything my max HR has gone down over the years. 4 years ago I think I hit 185 but now rarely hit 180 on full gas I’m about to puke efforts.

I’ve got one Garmin strap that started acting wacky due to build up of body salts. Thats why you are suppose to hand wash after every use, and then run in washing machine every 5 or 7 uses. Learned that one the hard way.

I’ve seen some people post a solution by cutting out the area between the two contacts. Hmm, can’t find any posts. Found something else interesting:
https://fellrnr.com/wiki/Fixing_Heart_Rate_Monitor_Problems

and DCRainmaker has several posts, worth giving this a read:

Hahaha. Well. This could very well be the problem, as I’ve only washed mine maybe once in years. That said I still think it is strange that the only 2 times this has happened was when I was surrounded by 20-50 other people. In each case it normalized once the pack had thinned.
I’ll give it a wash now and see what happens at the race tomorrow.

I’ve done Gran Fondos with thousands of people & do weekly group rides with 50+ and this has never happened. Highly doubt your Garmin is picking up someone else’s HRM. Likely yours is reporting incorrectly due to low battery or a dirty strap.

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Yup. You are right. The Garmin strap connects via ANT.
I’m going to try this wahoo one I have that connects via BT. It also has a lot less hours on it.

Yep. I have had this happen (reporting >200 hr during beginning of race), stopped happening once I replaced the battery.

My bet is that your strap is just flaking out. I’ve been through a couple Wahoo straps. Tried replacing batteries, and the soft straps. But it seems like once it starts flaking out, it can’t ever be trusted again. Like you, my max is about 182 and it’s not uncommon to see #'s like 230 when it starts going. In fact I haven’t worn one in a couple months because I haven’t replaced the last one yet…

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Same here. HIGHLY unlikely that the computer is picking up signals from other monitors. Earlier this year my Wahoo strap finally bit the dust after 2.5 years… sporadic connections, phantom heart rate (too low, too high), lost connection, etc. A new strap made it just like new.

Edited to add: The most likely reason for the HR registering 200 BPM (esp. if it happened at the beginning of the ride) was due to being multiplied by 2 inadvertently. I had this happen as well with my old strap (and also showing half). So your HR was probably 100, but due to fault reading or a faulty strap or bad probe connection to your chest was showing double that.

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Wash it once a week or at least rinse it daily. The built up salts and crap will result in no HR and/or crazy numbers.

Also, before you start your ride or run, wet the strap down before you put it on. Sometimes when the humidity is low, the strap is dry and your skin is dry, you can end up w/no HR and/or crazy numbers.

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Wow that didn’t last very long. My Polar must be at least 10 years old.

I’ve had 2 die in less that 4 years…

I’ll add myself to the list of people having problems with wahoo HRMs. Mine works sometimes but its super unreliable. Its junk. I bought it because of the Bluetooth connectivity.

The garmin strap I had previously was bomb proof.

Damn. That DC Rainmaker article says wahoo comes in on top in terms of reliability
(this is from 2012 so may be irrelevant)

"In general, the Polar straps tend to be far better than Garmin straps… Further, the most recent Garmin straps (2nd generation soft straps) tend to be better than the first generation soft straps (or rubber straps), though still not perfect. Most of the ANT+ straps are made in the same place and just rebranded for their respective companies, hence why they generally all act the same (companies can choose which level of strap to buy). On the ANT+ side, the one strap that offers me the least trouble is actually the Magellan Switch/Switch Up HR strap. In talking with them, they paid a bit extra for their strap over the standard offerings – which probably explains why I get virtually no spikes/dropouts.

On the Bluetooth Smart side, the Wahoo Blue HR strap is really solid and I don’t think I’ve ever seen any spikes/dropouts with it. I know they spent a lot of time on the firmware of the strap itself (quite uncommon) addressing the problem. Similarly, I haven’t seen many problems with the latest Polar Bluetooth Smart strap (H7) either. But, back to fixing those straps you already have."