Garmin Vivoactive 3 HR accuracy

Hodders · 24 Feb 2021 at 18:06

Does anybody else's Garmin under-read HR at the start of activity? Mine does. I stopped to take my HR manually at 4min in and it was about 160 to 165. My vivoactive 3 was reading 120. After about 8 minutes it was fine. Wierd... Blue line is what I reckon it should have been saying.

Any tips?

touch · 24 Feb 2021 at 18:17

Maybe not making good contact with your skin then when you start sweating more that helps it contact. Maybe try wearing the strap a bit tighter or wet your skin under it first?

Hodders · 24 Feb 2021 at 18:20

I'll try the 'sweat' idea. Cheers. Although it reads fine during the day.....

Merlin5 · 24 Feb 2021 at 19:45

Hodders said:
I'll try the 'sweat' idea. Cheers. Although it reads fine during the day.....

I must admit I haven't tested my Vivoactive 3 to know if it under reads at the start so that's something I'll try. But I always wear mine two fingers width up from the wrist bone and quite tight (8th or 9th hole for me). Check out this article with illustrations.

https://www.suunto.com/en-gb/Content-pages/what-should-you-know-about-wrist-heart-rate2/

wonko · 24 Feb 2021 at 19:54

Is this while walking/running? My VA3 had a habit of recording cadence instead of HR, and it could flip from one to the other during an activity. I remember doing a search and finding others reporting the same. I solved the problem by getting a fenix - it's in a different class!

Hodders · 24 Feb 2021 at 22:10

Cycling, so cadence shouldn't be an issue.

Really helpful replies, cheers all.

Hodders · 26 Feb 2021 at 18:00

Tried a slightly tighter strap and a bit of spit on the back of my wrist before I started - worked a lot better... Cheers....

Merlin5 · 28 Feb 2021 at 18:16

Hodders said:
Tried a slightly tighter strap and a bit of spit on the back of my wrist before I started - worked a lot better... Cheers....

Great stuff. On another note, I'm pleased with the calorie accuracy of my vivoactive 3. I was walking in the high street today doing mostly shopping. Covered 4.3 miles over 2 hours and it said I'd burned 473 calories. According to google "A rule of thumb is that about 100 calories per mile are burned for a 180-pound person and 65 calories per mile are burned for a 120-pound person."

Well I'm 173 pounds so those calories sound correct, give or take. Accuracy is important to me because I want to know I'm not eating more than I should when those burned calories are added to myfitnesspal which basically says I can eat those back.

wonko · 2 Mar 2021 at 13:40

Garmin seems pretty accurate in estimating calories for me too - for a while I was roughly counting calories and the deficit from Garmin's calories burned estimate correlated well with the rate I was losing weight. I gather that it's more accurate if you wear it regularly and enter details like weight and max HR.
I do suspect that a lot of people considerably overestimate their resting and active calories, and are then disappointed when they don't maintain/lose weight. My 'rule of thumb' is that I burn over 3000 calories per day on average (2000 resting and 1000+ active) and adjust the biscuits and wine accordingly.

D.P. · 4 Mar 2021 at 20:55

optical heart rate is fairly useless when exercidiu. Works well to get resting HR.

Whwn working put if your care about specifics get a chest strap.

wonko · 7 Mar 2021 at 14:07

Out of curiosity I tried a chest strap this morning and compared the results to the optical HR sensor on the fenix. There was very little in it - comparing the traces the chest strap was a bit quicker to respond to fast HR changes but the measurements were very close (including at the top end).
This was on a trainer bike in Zwift though, so the watch wasn't moving much - I can imagine if you're running with arms bouncing around it could affect an optical measurement. It may also be that earlier generations of optical sensor don't perform so well?