Heartrate suddenly not accurate

[Lora17]

I've seen a few of these issues on the message boards but nothing recently. 

Had this watch almost a year, no issues until this week.

I just did a 30 min workout on elliptical, and I usually get about 30 active points with about 140 bpm during workout. The past week it's not even reaching 100bpm during.

I even checked after the workout manually. My watch was still reading 97 but manually I was at 126bpm.

What is going on?? 

[Guy_]

Hi @Lora17  - may be a restart or a clean of the watch may help 

[Lora17]

So I experimented today on the elliptical and instead placed the type of exercise as "workout"... And it actually started reading my heartrate properly??

Why?? What is the difference between putting your exercise as a workout vs elliptical?? 🤔

[t.parker]

@Lora17 no difference. From my experience, I have seen Sense very accurate on certain occasions while I changed nothing at all. Don't look for logic in it because there is none. I have workouts for which half of duration matches the chest strap but suddenly something makes the HR very inaccurate for the remaining time. There is no pattern to the way sensor behaves. It is what it is.

[Guy_ · Accepted solution]

@Lora17  - there seem to be those whose watch under reads and those whose watch over reads.

What is known is tattoos affect the reading, so it is possible skin colour, hair colour, age ( how veins react and are/become closer to the surface during movement) , how well positioned the watch is to what it is measuring, etc. Or maybe variance in the watch sensor itself.

Generally it can be systematic per watch/person/exercise/movement.

In my case it over reads by nearly double systematically during the same exercise. It takes a while to get there and a while to come to normal after.

The only thing that seemed to make it accurate for a short while was to do a Shutdown and restart. Possibly changing a watch state may have a temporary effect.

As @t.parker says it is what it is.