Forums >Gears and Wears>Garmin Heart Rate
How can it be so inaccurate?!?! Easy run today, HR showing 160. Stop running, measure HR manually, it’s 130. Tighten watch, Reset watch, continue running. HR still measuring high with watch, normal when checked manually. I mean, I can see it being off by a few beats, I can see if I was wearing it too loose, but to be consistently 30 or more beats off even after tightening on wrist, restarting, etc. What the hell?!?
800m: 2:20.3 (2015) | 1 Mile: 5:13 (2016) | 5K: 18:32 (2010) | 10km: 39:55 (2012) | HM: 1:28 (2013)
I have a suunto but wrist HR just seems to be quite a dicey technology.
(warning: anecdote) Mine was great when temperatures were above 50F but since we've hit Autumn, it's been almost totally unreliable. Today I did a tempo run by effort (exceeding current VDOT paces) and I kept getting readings of 145-155 which is that crummy grey zone between z2 / easy running and Threshold but I can assure you I was working harder than that. During my cooldown it kept reading 16x would I might believe during the beginning of the tempo.
1600 - 5:23 (2018), 5k - 19:33 (2018), 10k - 41:20 (2021), half - 1:38:57 (2018), Marathon - 3:37:17 (2018)
I realize that it’s not the most accurate means of getting HR, but I didn’t think it could be so far off!
not bad for mile 25
Interesting. My Garmin seems highly accurate. Maybe it has to do with skin tone and vasculature in the wrist.
What is your skin tone and vascularity like? I’m pale and pretty veiny. Though the veins in the wrist are pretty small anyways
I hesitate to say because I don't know what is best for the HRM, but yeah, I'm pretty light complected and veins pretty pronounced. I have checked my Garmin both resting and running, and it's been spot on. Tried a chest HRM once, and its results were pretty iffy compared to my watch, but the chest test was several years ago.
I'm going to go out on a limb and say that the actual watch makes a difference too. My experience with chest strap monitor was that it took some time to sync in, but once it did it was rock solid (Garmin 405 or 410 - can't remember exact model). Next Garmin (225?) was wrist based and had a gasket on the back to help keep out ambient light, measured against previous watch seemed close. Current watch, 235, seems prone to "cadence lock" and I usually run with HR monitor off these days. Light sensors are known to work better on lighter toned people, so that shouldn't be the issue for you (from self descriptions). And it is entirely possible that you got a "lemon" - I would check with DC Rainmaker reviews for your watch to see what he says about it and the accuracy.
Also note, for about 2 weeks I had a fitbit charge watch and recall testing it against the Garmin 225 and 410 and the two garmins were within a couple beats of each other and the charge was10 to 15 beats off of that. The GPS also seemed less accurate on the charge and I ended up returning it and retiring the 410.
Ray
SMART Approach
It happens to me randomly on my 235 wrist model. I can now usually catch it before runs if my walking around HR is showing high before starting. I shut off watch and restart and it is always just fine after that.....until the next time 10 runs later.
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I have the 245. I have had success sometimes with restarting the watch to get the HR out of some sort of HR "lock," but it didn't work at all the other day. I guess I'll just keep my eye on it and not rely on it. It kind of bums me out, though, because I would like to have a somewhat reliable and inexpensive way to monitor my HR without having to stop and check it manually.
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Hi Kimba, it's good tool see you around, I hope you got better from the injuries.
As for the watch, I believe it has to do with wrist circumference. Garmin specifies on the product page what are the wrist circumferences it's built for.
My wife had the same issue with her FR645, I've noticed that the Fenix 6s fits smaller wrists, and now it works much better for her.
Most watches fit wrists that are 125mm and bigger in circumference. The 6s fits 110mm and up. I believe there are 2 other "small" models, but I can't remember right now.
PRs: 1500 4:54.1 2019 - 5K 17:53 2023 - 10K 37:55 2023 - HM 1:21:59 2021
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Hey there, Flavio! Yes, I’m all healed up. But not training for 1/2 and couldn’t keep up with that thread, lol! I checked it so sparingly that when I checked I was so far behind that it stressed me out!
My wrist is probably in the small side, but I’ll def check. Thanks for the info!
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I'd say it depends upon the watch and the weather conditions that your arm is exposed to. This applies to the previous TomTom GPS watch that I had (which, at the time, had the best sensor on the market). If the weather is cool/cold and your arm is exposed (i.e., you're wearing short sleeves), getting a good lock on heart rate can be a challenge until you are fully warmed up.
I own both a Fenix 5X and 6X (my 6X hasn't been through cold weather yet). The 5X did a reasonably good job of tracking with a chest strap monitor. Because of its memory capacity and characteristics, it's possible to use a chest strap monitor (I have two) and have it record at the same time as the wrist based system so that you can have direct, second-by-second comparisons. There's a widget for this and requires the chest strap HRM not to be "registered" tot he watch, otherwise the chest strap will override the wrist based data. Wearing long sleeves, a light jacket, or even sleeve warmers tends to alleviate the problems with cold arms I observed with wrist based data. It typically reads low and then, once it gets locked in, will suddenly jump to a higher rate that is more accurate and that is unrelated to cadence. I haven't had the cadence lock phenomena that others have reported and I do run with either a Stryd footpod or the Garmin Running Dynamics pod. So I do know my cadence very accurately.
On the whole, the averages for HR over a run of more than a few minutes and of sufficient intensity to get the heart rate over that of a fast walk will come within a couple of beats per minute of each other. In run/walk mode or doing HIIT, you can see the difference in response times. There is a lag of about 20-30 seconds between a change in intensity and a change in HR. The difference between the chest strap and the wrist monitor is on the order of 10-15 seconds. The chest strap responds much more quickly to changes in intensity the the wrist based monitor. Generally, it's not a problem unless you are using one of the more advanced watches that having training suggestions that are based upon HR data.
Remember, YMMV!
PR's--- 5K 24:11, 10K 49:40, 10-Mile 1:26:02, HM 1:56:03, Marathon 4:16:17
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Hi Kimba, it's good tool see you around, I hope you got better from the injuries. As for the watch, I believe it has to do with wrist circumference. Garmin specifies on the product page what are the wrist circumferences it's built for. My wife had the same issue with her FR645, I've noticed that the Fenix 6s fits smaller wrists, and now it works much better for her. Most watches fit wrists that are 125mm and bigger in circumference. The 6s fits 110mm and up. I believe there are 2 other "small" models, but I can't remember right now.
I have a very small wrist. And even with the smaller Garmin 735, I have never been able to get a reliable HR reading from the watch. So I just go with the strap.
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On my run yesterday I looked down and my HR figure seemed excessively high. Thinking about this thread, I stopped and took my pulse, and indeed, it was indicating way too high; probably a case of cadence lock. So, maybe disregard what I said earlier.