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Optical Heart Rate garbage for first 9-10 minutes of run

As the title says the OHR on my 645M is garbage for the first 9-10 minutes of my runs. After around 9 minutes the HR suddenly jumps about 20 bpm to a figure what I’d expect it to be.
The way this is happening makes me think it’s not a limitation of the optical sensor but a software issue maybe. I’ve attached 4 photos of my last 4 5k runs and a comparative one from when I used a chest strap. Why is it taking my watch 10 minutes to catch up with my true HR? ciq.forums.garmin.com/.../1371420.jpg ciq.forums.garmin.com/.../1371421.jpg ciq.forums.garmin.com/.../1371422.jpg ciq.forums.garmin.com/.../1371423.jpg ciq.forums.garmin.com/.../1371424.jpg

0 bigdwazda over 6 years ago

Mine worked ok again tonight, however, I do see a sudden 10-15 beats rise around 14 minutes or so in. It then looks fine for the rest of the run.

I think it's one for Garmin, they are normally pretty good when I have dealt with them.

0 jkissane_ over 6 years ago

I've seen similar with very high HR readings when I was doing an easy jog, doing a soft reset fixed whatever was wrong with it but of course means you have to pause the activity, do the reset & wait ~30 secs for it to come back to life before starting off again. These days I just ignore the readings from the OHR & use my old chest strap whenever I care about seeing HR data.

The fact that a soft reset seemed to correct the problem at least for a while made me think it was a software issue rather than hardware, I reported it to Garmin but the case really went nowhere.

0 PatrickNSF over 6 years ago

I just had another run where the heart rate didn't even get into my zone 1 for the first 8+ min Utes of my run, despite having the watch on and ready during my warmup. I filed the issue with Garmin today.

Has anyone heard back from them as to whether it's a hardware vs firmware issue? My former 935 seemed to lock in more quickly.

That being said, once the 645 locks in it seems to be working well for me.ciq.forums.garmin.com/.../1375873.png

0 Former Member over 5 years ago in reply to 777Steve

Yes I’m having the same problem.. frustrating. Start a run like I always have.. finish run and look at my hr data to see that it reads very low for the first 5-10 minutes, then suddenly jumps to 160-170 ish where it should be at the time. When I first bought the watch 5 months ago up until now I haven’t had this problem. I haven’t tried the power cycle prior but I wear it all day and shouldn’t have to. Garmin, any help with this would be appreciated. Love my 735xt up until this wierd hiccup.

0 Former Member over 5 years ago in reply to Former Member

Love my 735xt up until this wierd hiccup.

Check the 735 forum. Maybe there's a problem and a solution with that watch.

0 Former Member over 4 years ago

777Steve said:
I’ve

0 Former Member over 4 years ago

Today's run. I would expect all ~145 but it increased although I didn't feel that i was more tired...