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High difference in HR between chest strap and Swim 2 (over 40 bpm)

Hi,

today, again, I noticed a massive deviation between the HR I saw on the Swim 2 and my ANT+ chest strap.

I did some workout on my ergometer. As the chest strap I own does not work under water but is somewhat comfortable to wear and I always use it on my ergometer. It is from Polar and uses ANT+ and unfortunatelly this standard is not supported by Swim 2.... but this is a different topic.

My ergometer can cope with it, so I use a different app to export my TCX data including the heart rate during training. During my last sessions I had a difference in HR of 20 bpm, which I consider already as quite high. Sometimes the HR measured by Swim 2 was according to the HR the ergometer showed, but mostly they differed by at least 10 bpm. But today, it was even worse.

When I was at 230 - 250 Watt and a cadence of somewhat between 90 and 100 after already having trained for 45 minutes, the Swim 2 showed a HR of 75 to 110 - but mostly on the low 100 or below 100 bpm side of HR. The HR transmitted by the chest strap was between 140 and 150, what I consider more likely than the one shown on the Swim 2. It corresponded to hwo I felt ;)

Has anyone ever experienced such high differences? i mean I don't care on a difference around 5 bpm between chest strap and HR measurement at the wrist. Is there something I can improve on wearing the watch? I wear it quite tight, as I prefer it not to move during exercise. I am used to a difference and when I still had my running watch from the same brand as my chest strap, there were minor differences - which is natural and I don't care.

But a difference of > 50 bpm?

Thank you for your support and any help to solve this problem.

Best regards,
Christine

  • Hi Christine,

    Wrist OHR measurements can be off sometimes. It is a software issue, the self calibration of the watch sometimes sucks. From my experience a multiply of 10 what happens. I often see 20-30 BPM jumps in the log. So if it is off, it is by a big amount, and if it is good, then you see only 1-2 BPM difference from the chest strap.

    BTW, Swim2 does support ANT+! For running I always use my ANT+ chest strap with my Swim2, and it works perfect.

  • Hi,

    thank you for your reply.

    I am used to the differences between Wrist measurement vs. chest strap. Was just confused that it was soooooo much off... With my Polar watch, if it was ten, it was a high difference... So I am really just wondering...

    Seems that my watch had some bad day yesterday, I noticed when I synced it that it didn't do HR measurement for over 12 hours... :/ I will keep an eye on it- and probably use my chest strap more often.

    How can I get it to work with the ANT+ chest strap? Tired for several times to get it going (in the watch - add sensor or however it is called) - but never succeded...

    Thank you and best regards,
    Christine

  • The only adding option is what you described. It works for me with a noname ANT+ strap and pod. Maybe Polar version is not compatible with Garmin.