Related

Polar H10 not working

4371050

Hi!

Starting from recently I've noticed that sometimes the watch doesn't get HR data from my strap at all. When it does, sometimes there are sudden drops to my HR.

This happened mostly when doing running workouts from my Garmin training plan.

I'm pretty sure the watch keeps its own optic HR sensor on even though it's supposedly getting data from the strap, I don't think this is ideal.

  • 0

    i am using H10 also with 965 and working perfectly (via ANT+ now). but it is my 2nd H10, the 1st one died (and had much bigger power consuption than normal, and couldnt be updated its firmware to the latest)

  • 0
    4371050 said:
    I'm pretty sure the watch keeps its own optic HR sensor on even though it's supposedly getting data from the strap, I don't think this is ideal.

    I think there are 2 possible reasons the optical HR sensor would stay on when an external HR sensor is connected (during an activity):

    1) you have Garmin Pay enabled, in which case optical HR is used to detect when the device is on your wrist. If the device does leave your wrist at some point, you will be prompted to re-enter your PIN the next time you use Garmin Pay

    2) a new-ish feature called dynamic source switching which is enabled by default and does 2 things:

    2a) it records both wrist optical HR and external HR for an activity, in addition to the HR that the activity uses (which could be either external HR or wrist HR - see next point). This means that the optical HR will stay on regardless of whether it's used as the source for activity HR at any point in time

    2b) for compatible Garmin HR straps (i.e. not Polar H10), the watch will use wrist HR as the source for activity HR if it determines that the data from the HR strap is bad. Note: this does not mean that the connection between the watch and HR strap was lost - in this case it means the watch thinks the data (signal) is bad - e.g. due to poor contact between the sensor and your skin - but the wireless connection between the watch and HR strap is just fine.

    Notes:

    - Garmin support article on dynamic source switching: [https://support.garmin.com/en-CA/?faq=Nf8r6ApX4d9lX0G0flEsVA]

    - dynamic source switching is not the same as "simple source switching", which is not new and works with all external HR sensors: if and when the actual wireless connection between the watch and external HR (e.g. due to temporary "dropouts", a dead battery, or the sensor just turned off for whatever reason), then the watch will switch to optical HR regardless of dynamic source switching is enabled or disabled

    - 2b) supposedly doesn't work with 3rd party straps, but 2a) always happens when dynamic source switching is enabled. (You can export the original activity FIT file using the Connect website and view it in fitfileviewer.com to see all 3 HR metrics, which allows you to see if and when dynamic source switching happened - which it shouldn't for Polar H10, and it also allows you to see if the connection between your H10 and the watch was actually lost at any point

    - I've personally noticed that when using a compatible Garmin strap with dynamic source switching enabled, my FR955 sometimes inappropriately uses the wrist HR when the data from the external HR is obviously at better (e.g. at certain points during interval workouts). Others have posted similar observations on the forums. This shouldn't be an issue if you do not use a compatible Garmin strap though. The only issue you would see is increased power usage due to the optical HR sensor staying on for the whole activity, even when you have an external HR sensor connected

    If you would prefer for the optical HR sensor to not be enabled while your H10 is connected, then disable dynamic source switching. This will not prevent the watch from switching to your H10 if there is a connection dropout. If you really want to prevent that, you would have to completely disable the optical HR sensor. But then of course you'd have gaps in your HR data

  • 0 in reply to flowstate

    I've disabled dynamic source switching, let's see if this works. Thanks for the thorough explanation.

  • 0 in reply to 4371050

    No worries!

    To be clear it won't solve your problem with apparent dropouts.

    It will only make it so that the optical HR sensor shouldn't stay active while there is a connection between your H10 and your watch.

  • 0 in reply to flowstate

    If dynamic source switching is not supported for a strap, then why would Garmin keep the optical sensor always on (assuming there's no Garmin Pay involved) even if the dynamic switching setting is enabled on the watch? 

  • 0 in reply to flocsy🤠

    I tried to explain this above, but dynamic source switching does TWO things:

    1) it always records wrist HR and external HR (when applicable), in addition to the activity HR, regardless of whether a compatible external HR sensor is connected

    (Garmin doesn't really explain this part)

    2) for supported Garmin straps, it will switch to wrist HR when it deems the "signal quality" of the external HR is bad (note: this means the signal measured from your heart by the strap, not the wireless connection between the strap and the watch).

    Yes, I realize that it would be sensible for Garmin to avoid doing 1) if 2) is not supported. 

    However, this is Garmin we are talking about. It probably wouldn't surprise you to hear that until fairly recently, you could not even disable dynamic source switching unless you had a compatible Garmin strap connected. This caused 3 problems:

    A) If you didn't own a compatible Garmin strap, you wouldn't be able to turn off dynamic source switching (it's on by default), meaning the optical HR would remain on for no good reason (as you implied above)

    B) Even if you owned a compatible Garmin strap, you would have to connect the strap just change the dynamic source switching setting. This was super annoying if you just wanted to turn it off

    C) It was impossible to change dynamic source switching from the Connect app ("real time settings"), since presumably the app wasn't capable of determining whether a compatible strap is connected. The setting was in the app, but greyed out.

    At least Garmin has rectified this by allowing the dynamic source switching setting to be changed at any time.

    If you don't believe me, go ahead and record a couple of runs with dynamic source switching enabled, using the 2 following scenarios:

    S1) no external HR sensor connected

    S2) external HR sensor connected, but it's not a Garmin sensor

    You will see that for S1, "wrist heart rate" will be recorded in addition to "heart rate" (via fitfileviewer). (Ofc in this case, both fields should be identical)

    For S2, "wrist heart rate" and "external heart rate" will be recorded in addition to "heart rate". (In this case, "external heart rate" should be identical to "heart rate", except for the times when "external heart rate" is not present, which would happen if there are any sensor drop outs.)

    If you then disable dynamic source switching and repeat the same 2 scenarios, you will see that "wrist heart rate" and "external heart rate" are never recorded.

    To be clear, I am not saying this is a sensible implementation decision, just describing what I see. I do think it would be more sensible to functionally disable dynamic source switching if a compatible Garmin strap is not connected.

    But at least the way it is now, you do get bonus functionality where the wrist hr is recorded in addition to "regular" hr.

    I also wish it was possible for "wrist hr" / "external hr" to be optionally recorded even if dynamic source switching is disabled. i.e. I own a compatible Garmin strap, and when dynamic source switching is enabled, sometimes it inappropriately switches to the wrist hr (it's very obvious that the data from the wrist hr is worse than the external hr, when this happens). I'd like to turn off dynamic source switching, but then I lose the bonus data.

    What I can't say for *sure* is whether Garmin in fact ever "dynamically switches" to wrist HR for a non-supported (e.g. non-garmin) strap. I mean, they say they won't, so I'm taking them at their word. (Again, this is not the same as when the watch switches to wrist HR due to a sensor dropout - this happens whether or not dynamic source switching is enabled, and indeed would happen even on old watches where the feature does not exist.)

Copyright © 1996-2025 Garmin Ltd. or its subsidiaries