I have just started using my first Garmin device, a Vivosmart 5. And I have a very annoying issue with the measured minutes of intensity. They are completely off.
I noticed the issue already after the first day, which I have spent almost entirely at my desk. My data claims that I have spent 414 minutes of intensity (48min moderate and 2x183 minutes high) which is completely absurd. Now, I am suffering from tachykardia, so I started experimenting with the settings.
- The first thing I did was turning on using heart-rate zones but leaving the predetermined zones intact. Which changed nothing.
- Then, I changed moderate intensity to zone 4 (instead of 3) and high intensity to zone 5 (instead of 4). Without effect, I still had a completely unrealistic amount of intensity minutes.
- Then I manually set the BPM values for the zones and did some experimentation. My current setting is 104 to 149 for zone 2 (!), 150 to 159 for zone 3, 160 to 169 for zone 4 and 170 and above for zone 5. Moderate intensity is still set to zone 4 and high intensity to zone 5. With this settings, even with my tachycardia, I should get zero minutes of intensity.
You may have guessed it already? I still have an absurd amount of intensity minutes. Here is an example of today: I did a 39:09 minute walk. I have spent the entirety of this walk in zones 1 (3:10) and 2 (35:59). My data clearly shows it. It also shows that the zones have been measured according to my BPM settings (104 to 149 for zone 2). But still, on the same data page, it says that I have spent 6 minutes in moderate and 32 (x2) minutes in high intensity. How can that be, when zone 4 (moderate) only should start at a heart rate of 160. How can that be, when I have spent the entire walk below 149 bpm?
After all that experimentation my best assumption is, that the switch for turning on BPM-zones as a measure for intensity minutes is just broken. It seems to me, even though you want to use BPM-zones, the device still uses the "Garmin-method" (aka *** method).
This bug has far reaching complications for me. I am also following my calory intake with another app. And this app draws activity data from Apple health. Since intensity minutes also seem to lead to a high amount of burnt calories, my nutrition app allowed me to eat and absurd amount of additional calories. If I would follow that, I would gain instead of loose weight. To circumvent that, I have disallowed Garmin Connect to write activity energy into Apple Health, so Yazio does not draw incorrect data.
I don't know how many hours I've spent during the last days to figure out all of that. But it certainly was time I would have loved to spent otherwise instead of doing the job of Garmin's quality control (is there any?)