haertbeat too high

Cees_2020 Registered Users Posts: 2
Apprentice Seeker
edited January 24 in TomTom Sports
I'm facing the problem that the haertbeat on the watch is far too high at the beginning of a run. It takes about 10 minutes before teh watch shows the real and lover haertbaet.
I've already restored the factory settings several times and ha ve the latest firmware installed
Any idea?


  • Drqili
    Drqili Registered Users Posts: 4
    Master Traveler
    I had the same experience. Sometimes the sensor is recording based on your cadence instead. So I tried to tighten the band, wear on the other wrist, change my arm movements to avoid this accidental lock to cadence. Sometimes long sleeve also affects the reading. It's frustrating indeed.
  • tfarabaugh
    tfarabaugh Posts: 16,939
    You can get spikes in HR due to the watch either losing the pulse signal and locking onto another signal, like cadence, or the cadence simply overpowering the pulse signal. 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 or when you are doing sprints with very high effort. You should 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 used to be a common fault with many optical HRs, not just TomTom unfortunately, although newer models have basically eliminated it. Optical HR also can tend to lag in measurements, so if you are doing intervals it can take a but to catch up, so it shows high HR during the rest periods. If you notice it while it is 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.
  • Cees_2020
    Cees_2020 Registered Users Posts: 2
    Apprentice Seeker
    Thx both Drqili and tfarabaugh. I do have a broader view on this issue yet.