I am interested in knowing what my resting heart rate is during the day. I've got plenty of chest strap monitors to use while exercising. Why not use one of those you ask? Two reasons - they work better while the the body is sweaty. They are giving me weird, improbable resting rate readings - low 40s. Hey I'm reasonably fit but I don't think so.
Anyway I want a brain dead ultra simple, cheaper the better watch that will give a continuous reading of heart rate. I've done a bit of checking and I see that these optical wrist heart rate monitors are most accurate at resting heart rate. Perfect. I don't want GPS, 50 functions blah blah blah. I don't want to have to use an app. I just want a reasonably accurate heart rate measurement. Do they make anything simple these days?
My impression is that the watches that allow you to record an ECG are the most accourate for heart rate. Such as Apple watch or Withings scanwatch. Maybe the Mii band for cheap and simple optical. Also have a read about ectopic heartbeats as well. They can cause improbably low heart beats.