But when it's inaccurate then it's usualy blatantly obvious. For example if you are out on an easy jog and it shows 188 bpm then that's your cadence, not your heart, unless something is going down really badly and then you don't need the watch to tell you that.
It's not like it will show 147 when the actual value is 134.
It's not like it will show 147 when the actual value is 134.