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Forerunner 35 HR not accurate

I really hope someone can help me here.. I bought my Forerunner 35 on 31 December 2016. When I go running, the HR and GPs is very accurate, love it. Although, I train 4-5 times a week at a Crossfit Box, and then the HR is VERY inaccurate. I"ll be in the middle of a workout when it feels like I"m almost at 100% of my HR , but when I look on the watch, it will say around 50 bpm... (my resting HR isn't even THAT low!!!) This is really disappointing, and the worst is, I don't really know who to talk to about this. Can I send it back to Garmin so that they can check it? I thought of buying a Garmin HR strap, but then what's the point of me buying a wrist based HR watch if I still need a strap aswell?

Does anyone else also have this problem? It's really annoying. Also, if I can contact anyone directly at Garmin, I will appreciate it SO much!!!!
  • Yep! Everyone with a wrist HR is having the same problems. Take a look through the forums posts and you'll see that it's all been discussed time and time again, ad nauseum.
  • This is really disappointing, and the worst is, I don't really know who to talk to about this.
    You've come to the right place to talk about it with fellow Garmin customers and product users.

    That's not the same thing as who you'd approach to try to get satisfaction, however.

    Can I send it back to Garmin so that they can check it?
    I'm sure you can (Product Support links here), but remember checking would be against what Garmin holds as functionality (and/or performance) as the device was designed and engineered, and not using your expectations as the standard.

    I thought of buying a Garmin HR strap, but then what's the point of me buying a wrist based HR watch if I still need a strap aswell?
    That's a reasonable question. Personally, I wouldn't dream of wearing a chest strap heart rate monitor 24×7 to track my resting heart rate, or even my heart rate while I'm working at my desk (if that's of any interest).

    Wrist-based optical HR sensors do not work particularly well with high-intensity interval workouts in which the user's heart rate changes rapidly and quite significantly, full stop.

    For what it's worth, I used a FR235 and its built-in Elevate optical heart rate monitor for a year, and I didn't have any problems with it for running. I believe that's the same one used in the FR35. However, now I've passed the FR235 to my girlfriend to use, and I bought myself a FR630 (with HRM-RUM4 chest strap as a bundle) as a replacement. The RHR stuff was mildly interesting, but ultimately not a genuine concern.
  • FR630 better for HIIT

    You've come to the right place to talk about it with fellow Garmin customers and product users


    Thanks for your reply! Do you think i should rather get the FR 630 then? Is it better for HIIT training? Will probably be cheaper to get the chest strap and only wear it when working out.
  • Do you think i should rather get the FR 630 then?


    I see no point in doing that. The 630 has no optical sensor, so you'd have to use a chest strap anyway. And a chest strap you can use as well with your FR35.

    Is it better for HIIT training?


    Hard to say. The 630 has more features, especially for hardcore runners, but for HR monitoring there is no difference, as long as you use a chest strap.
  • Do you think i should rather get the FR 630 then? Is it better for HIIT training? Will probably be cheaper to get the chest strap and only wear it when working out.
    I don't know whether you should. I got my FR630 bundle because it was discounted to A$299, when the street price of the chest strap alone is around A$140, so I'd say that's a damn good price compared to other options. I'd imagine the bundle would indeed be better for HIIT, but remembering and taking the time to put on the chest strap each time could be a chore, and it's not the most comfortable thing (although it isn't that bad either, and I mind it less than when I used a Wahoo TICKR-X occasionally last year).

    The touchscreen on the FR630 takes a bit of getting used to, and in some ways I still prefer the FR235. If the FR235 was being offered at A$250 or thereabouts at the time (I paid A$340 for my first one, a year ago), I'd have bought a second FR235 and given the new one to my girlfriend to use, since I was quite happy with mine. (The optical HR sensor would not be any better than that on the FR35, I'd imagine, but there is always the option of using a chest strap HR monitor with it, and it supports custom workouts and Connect‑IQ which the FR35 doesn't).
  • The heart monitor works off movement, not heart rate. I noticed it wasn’t accurate then discovered if you shake your arm up and down rapidly  for about  ten seconds your heart rate will show 125 to 130. It’s movement, Garmin knows this and sells the watch as a heart monitor. 

  • Hi, was wondering who I can contact. I bought a Garmin Forerunner 35 in Nov and overall have been very happy with it... I'm finding tho that the heart rate is not accurate at all...I only jog on the spot so I'm comparing apples with apples... somedays it registers a hr of btw 170 and 190 consistently for the hour and the next day it doesn't even get to 120... seeing that it's not even 6 months old I'm sure I can get a replacement but who do I contact ?

  • Hi, was wondering who I can contact.

    At Garmin Support you can call, chat, or email.

  • Chest Strap HRM is for Timed Activities Only - It Does not Work when you are not doing a timed Activity. (FR35)

    It is the Best Solution for Cycling, Running and Specially for Gym, Crossfit , Weight Training.

    Another tip is to Wear your Watch Further up the Wrist and a little tighter.

    All Wrist Based HRM have Exactly  the same issues Garmin or Non Garmin.

    The Watch has to Hunt for a Pulse on your Wrist. Blood movements Inside your Body affect them as does the Cadence of Your Exercises Body Movement.