TomTom Runner 3 cardio optical heart sensor

mdmartin
mdmartin Registered Users Posts: 3
Apprentice Traveler
edited January 24 in TomTom Sports
I think there is a problem or default in my optical heart sensor. Sometimes he gives the correct data (50bpm), but suddenly he just goes to 80 bpm in 5 sec.
When I go running, my bpm normally lies around 140, but with this watch, it lays around 190.
Somebody knows what to do?
I already sent an email to tomtom, but no answer so far.

Thanks!

Comments

  • tfarabaugh
    tfarabaugh Posts: 16,943
     Superuser
    Spikes in HR are generally from poor blood flow producing weak pulse strength, so the watch reads cadence instead. This is most common in running and is particularly apparent early in a workout or during a non-intense workout when you are not warmed up. You have to think of the optical heart rate as an algorithm that is attempting to track a signal in a set frequency range (30-230 or whatever it uses). If the pulse signal is weak it latches onto the next strongest rhythmic signal, which is your cadence in running and the vibrations of the bike in cycling. For most people who experience this while running it spikes to around 180-200 bpm which is also the average cadence people run at. Additionally, each person has a different HR signal ‘strength’, depending on a range of factors, so some are prone to get it more than others. But usually their signal strength is lower for the first 5-10 minutes until they warm up properly. So in that time, it is prone to latching onto cadence, which is a common fault with all optical HRs, unfortunately. If you notice it while it happening you can try moving the watch a bit or briefly pausing your run so it loses the cadence reading and latches back onto HR, which I find usually corrects it. I generally pause the watch, stand still for 20-30 seconds and will see it immediately start to drop. Once it gets into a more reasonable range and the pulse reading stops dithering (dithering is when it is not getting a good signal and it is a lighter grey in color) I start up again and it stays true for the rest of the run. You can also try switching wrists and the position on the wrist. I find I got better readings on my right wrist over my left and some people find they get better readings if the watch is on the inside of the wrist rather than the outside. It also helps if you warm up a bit to get your blood moving and your HR up so it is producing a strong signal. Play around with it and see if any of this helps you. The challenge for the manufacturers of optical HRs (and this is a common issue with all brands, my Scosche also does it) is to figure out how to factor out the other noise that is overriding the pulse signal without also factoring out other important data.

    I hope this helped answer your question. If so, please mark it as a solution so others can look for it if they have the same question.
  • mdmartin
    mdmartin Registered Users Posts: 3
    Apprentice Traveler
    I'll try the stop running part for 20 seconds. All the other options you gave didn't work for me :/
    So it's just standard, there's no reason to expect a default then?
  • tfarabaugh
    tfarabaugh Posts: 16,943
     Superuser
    It is just the nature of the technology unfortunately and happens with all optical HRs, not just TomToms. Make sure you have a Go before you start and I generally wait with it on the Go screen for a few minutes to get a good lock. I also do some light warm-up to get my HR up a bit before starting which helps. Make sure you are wearing it at least 1" above the wrist bone and fairly snug (not so tight to cut off circulation but not so loose to allow light to seep in).

    I hope this helped answer your question. If so, please mark it as a solution so others can look for it if they have the same question.
  • mdmartin
    mdmartin Registered Users Posts: 3
    Apprentice Traveler
    It didn't work. I stopped for like 30 seconds and it dropped to a reasonable heartrate. As soon as i started again it got up to 190 BPM. I can't imagine running 10 km at 190 BPM while still being able to talk?
    Just now I was resting in my bed for 30 min and I had 120 BPM.
    This can't be normal, right?