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Heart rate measurement suddenly too high on FR35

Hi there,
I have the Garmin Forerunner-35 for 8 days now, and the first 7 days I was quite happy with the device. I tested it with another heart rate device during running and cycling and I was quite happy with the result. The wrist sensor did a good job regarding the heart rate accuracy (although you need to wait one minute before the FR35 displays an accurate value)
But now I suddenly experienced a big error with the heart rate measurement during my run. The first half hour was ok, but then suddenly the displayed heart rate value was way out of my actual heart rate. (continually +50 bpm too high) I tried to solve this by restarting the workout or cleaning/drying my wrist, but nothing helped.

The only difference with the other workouts....the outside temperature was quite lower (at around 0 C / 32 F) . So I suspect that the FR35 will give wrong heart rate values when the surrounding temperature is too cold. (My wrists were also pretty cold, since I was wearing short sleeves)
Does anybody else experienced the same?
If this is the case, I think I will not return the FR35, since this rather cold temperature is not so frequent here (The Netherlands)

0 SUSSAMB over 7 years ago

I suspect it's more a case of when you get cold blood is naturally drained away from your skin surface, it's part of the body's way of trying to keep your core temperature correct, it's why people tend to look pale when they are cold. This makes the heart rate difficult to detect accurately.

0 Jim-FX over 7 years ago

Thanks, I think your right. Next time I wear long sleeves when it's that cold.

0 David_I over 7 years ago

Heart rate measurement too high on FR35

I suspect it's more a case of when you get cold blood is naturally drained away from your skin surface, it's part of the body's way of trying to keep your core temperature correct, it's why people tend to look pale when they are cold. This makes the heart rate difficult to detect accurately.

Hi Sussamb,

I had exactly the same error in my last worrk-out. HR was shown as 50 to 60 bpm too high. HRM maxed out at 199 BPM on a slow treadmill run!. The explanation of cold weather, however, doesn't work for me. I'm in Bangladesh and the run was hot, with my wrist being wet from sweat.

I previously used the chest strap which seemed quite reliable except in cold weather when the contacts weren't damp, but I would regret having to go back to the chest strap as the optical sensor is much more convenient.

0 Carmen_F over 7 years ago

When it was cold I had too low HR, after a while it was more accurate. How tight was your FR? My arm is a bit thinner when it ist cold. So slipping up and down may cause a too high HR. The same if you sweat a lot.

0 DonKWiley over 3 years ago

My new FR35 is reporting a HR about 30 bpm higher than it really is. This is all the time. This is NOT a function of not wearing it properly, skin conditions, temperature, etc. IT IS DEFECTIVE! I am returning it and Amazon is sending me another one under warranty. Hope it works properly!

0 JoeD over 3 years ago

I have this Heart rate too high happening Intermittently as Well on FR35

0 6884548 over 3 years ago in reply to JoeD

My Garmin FR35 has also displayed high heart rate intermittently for more than a year. In my case my resting heart rate is 60 and my exercise target heart rate is between 100 and 110. Today my FR35 displayed 140 after I returned from a brisk walk. At the same time I also measured my HR on an AliveCore KardioMobile 6L EKG device, which showed my HR to be 74. This problem and difficulty syncing data between my FR35 and my Samsung Galaxy Note 5 cell phone are why I will replace my FR35 with a more accurate device if I can identify one. I have been planning on replacing my Note 5 with a Note 20 and my FR35 with the new Galaxy Watch 3, but only after Samsung gets the HR/BP/EKG apps working and only if they turn out to be more accurate than my FR35.

0 JoeD over 3 years ago in reply to 6884548

Buy a Chest Strap for your FR. The Wrist Based HR Machines can pick up the "Cadence" of the Workout and report it as HR. A Chest Strap based Watch will give more accurate readings except that the strap can get over soaked with sweat and also fail to give accurate readings but is easily sorted out by wiping it down.

Wearing the Watch Strap a little tighter and further up the wrist will help as well.

When I do Weight Training I wear mine on the Ankle and it works 100% then.

I still want to try on the ankle with a long sock over it for running.

0 cbeevis over 3 years ago

My Forerunner 35 has been reporting super high heart rates when I'm doing easy runs. I've had it and worn it every day for close to two months now. I was worried because it was recording near max heart rate even when I wasn't pushing my pace, and I was getting concerned that I was way out of shape - it was telling me my VO2 max is in the bottom 20 per cent of my age and gender and I couldn't figure out what was going on, because I certainly wasn't feeling like I was going to pass out or like I was exerting that much effort. This is happening both in warmer and colder temperatures outside over the course of two months, so I don't think it's connected to temperature. I am a pretty active woman, and train 5 or 6 days a week.

Today I participated in a virtual "dance party" for fun and wore my watch. I noticed that even though I was exerting myself quite a bit, my heart rate never climbed higher than 30 below the highest rate I've tracked while running, even when I was feeling quite out of breath.

So, I'm wondering whether my arm movement or cadence while running is affecting my heart rate. Is that possible? And if so, is there a way to fix this?

TIA

0 3715759 over 3 years ago in reply to cbeevis

Make sure the watch is worn properly, tight but not too tight. If you move the watch your skin should move in the same direction. https://www8.garmin.com/manuals/webhelp/forerunner35/EN-US/GUID-F2E7E0A9-FB44-4297-BF4D-D0C31C400C45.html

Arm movement should be no problem as long as the watch doesn't slide on your skin, hope my explanation is clear, I'm Dutch, not a native English speaker...

With my FR35 some sharp HR spikes occurred while walking, never happened while cycling, also not while riding on cobblestones with my road bike.