Runner 3 and heart rate — TomTom Community

Runner 3 and heart rate

Patricia KingPatricia King Posts: 1 [Apprentice Seeker]
My maximum heart rate has been calculated as 154. The calculation was done during a medical sports test with heart and lung equipment at the hospital. The heart rate on my watch sometimes hits 220 generally at the beginning of a run when I am only warming up. I returned my watch to Tomtom to be checked out but there is no change in the HR registration. This sucks as I am training for a marathon at a specific HR. Is this a common problem and does anybody have a solution to it?

Comments

  • tfarabaughtfarabaugh Posts: 15,793 Superusers
    There are two issues around heart rate using optical HR monitors, and these are on all devices, not just TT ones: low heart rate and HR spikes. Low HR is often seen in rowing, cycling and weight lifting. Any time you do an activity that squeezes or tenses the forearms (like the pull stroke in rowing, bearing down on your handlebars in cycling, or virtually any weight lifting move) you are squeezing the blood vessels the watch is reading, so it sees this as a reduced pulse. It is not that the watch is having a problem reading your pulse; it is that your pulse at the wrist has dropped because you are temporarily cutting off blood flow to the vessels it is reading. I have experienced this with every optical HR I have used, including a Mio and a Scosche unit. For these sorts of activities, you are better off using a chest strap synced to the watch if getting a more exact reading is important to you.

    There is an additional issue with optical HR beyond low HR. You can also 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 is a common fault with all optical HRs, not just TomTom unfortunately. 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. 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.

    In a nutshell, it is a limitation of the technology and the way TT has implemented and there is nothing you can do to change it other than ensure you have the watch properly positioned and are warmed up a bit.
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