I love my Garmin. Without pressing a button, it shows me the time, battery, heart rate, temperature, daily steps, and calories burned.
But for proper exercise measurement, in particular heart rate, I ignore my Garmin completely. The optical heart rate sensor reliably outputs garbage data. On an easy run, where I know I’m around 125 beats per minute, my Garmin can display anything from 100-180 beats per minute. It’s categorically useless for any meaningful measurement.
So for cardio I ignore the wrist watch and rely solely on my chest strap heart rate monitor. It’s immensely accurate and adjusts within a second based on changes in intensity.
It baffles me how a device can function so well for some things, but so poorly at others. Because I understand the limitations of the device, I can work around them by using other technology to get the data I need. But I’m sure there are many users out there who believe the garbage data is true, and that really annoys me.