Why is the heart rate monitor suddenly giving crazy values and how do I fix it?

RunningIsHard

Been using my Runner Cardio GPS watch since October 2016. Until this past week, I’ve had no particular issue with the heart rate monitor. It has been as accurate as it needs to be. Then last week, I responded to the push notification/suggestion to wear the watch for a couple of hours to get a resting heart rate. This involved manually switching on the heart rate monitor. Perhaps it’s merely a coincidence, but since that day, the heart rate monitor has given crazy values when I run, For example, measuring 169bpm at the very START of the run, rising to 192 bpm. I have cleaned the contacts with alcohol, but things still aren’t right. The way I run/walk, once I’ve warmed up, my heart rate normally hovers between 125bpm and 140bpm. I’m looking for ideas on how to get the monitor back on track, and how to avoid the problem in future.
As a side question, where do I find the data for resting heart rate that the watch monitored? Does the software automatically use that data to set the resting heart rate threshold?
Thank you.

tfarabaugh

Resting Heart rate is on the MySports page under Progress>Activity Tracking. As to the HR problems, that sounds coincidental and possibly sue to it getting colder out. You 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. 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.

You can also try a factory reset in case it is a firmware issue, but it is likely as described above. It could also be that the sensor is dying as the watch is 4 years old and obsolete, in which case it is time for a new watch (not a TT as they went out of business almost 3 years ago).

RunningIsHard

Thank you for your very thorough and helpful response, @tfarabaugh. I will try those fixes. Good tip about TT - I was unaware. Recommendations for something in equivalent price range should I need a new one? And would my historical data be transferable to the next App?

tfarabaugh

RunningIsHard wrote: »

Thank you for your very thorough and helpful response, @tfarabaugh. I will try those fixes. Good tip about TT - I was unaware. Recommendations for something in equivalent price range should I need a new one? And would my historical data be transferable to the next App?

Look at the newer Garmins (check dcrainmaker.com for reviews), they are the really only viable options these days as they control the market. You can download all of your activity files in a zip from TT and would then need to manually upload them to Garmin Connect, there is no automated transfer.

RunningIsHard

Thank you again @tfarabaugh.