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Calorie count way out on forerunner 235 since I connected MyZone HR monitor

Former Member over 5 years ago

Ok so I've seen lots of people have had this problem but haven't seen any solutions, I wondered if anyone has heard anything from Garmin themselves?

Before I connected my HR strap there was no issue at all with calories or training level but since I have connected the strap it's saying I've burnt barely any calories!

As an example, last week I ran a half marathon and according to my MyZone HR monitor I burnt 1894 calories. My watch, and therefore my Garmin and Strava apps, say that I burnt 370 calories for the same run!

This has happened on every single run since I connected my HR monitor. I'm tempted to just not have them connected but the whole point is that it's meant to make my stats more accurate, not the exact opposite!

Any solutions? Thanks!

0 trux over 5 years ago in reply to Former Member

my weight was only entered when I first got the watch 2 years ago.

You better keep updating it regularly, if you want accurate Calories calculation. A small change in weight my influence the result considerably.

0 Former Member over 5 years ago in reply to trux

Will do. I'm sure it does make a difference but it should surely still be in the same ballpark (as I said, when I don't run with my HR belt it gives a reading that makes sense, so that isn't the problem).

Thank you for your help!

0 trux over 5 years ago in reply to Former Member

I finally realized the real culprit of the big difference between values given by your MyZone HRM and those of Garmin's own HRM (regardless whether internal wrist OHRM, or an external HRM chest belt). Garmin uses the technology developped by Firstbeat (Norvegian company specialized in medical research).

And for the Calories calculation, they use (besides others) an important feature available in Garmin's HRM's - the Heart Rate Variability (HRV) data. It allegedly allows for Calories estimations accurate within 5-7% of laboratory measurments.

However, not all HRMs of other manufactures have the capability to report the HRV, which seems to be the case also for your MyZone HRM. Either it does not detect the HRV data at all, or it sends it in an incompatible format. You may want to ask them about it.

Read more about the Firstbeat technology on their website on the page Calories Burned

0 trux over 5 years ago in reply to trux

... in other words, the solution seems to be using only HRMs supporting the Heart Rate Variability data, and compatible with Garmin, as long as you need accurate Calories estimates. For plain HR monitoring, and if you do not care about features like sleep monitoriing, stress monitoring, body battery, and similar, devices without the HRV data are sufficient, though.