Do you trust your fitness tracker's"calories burned"?

crazyravr wrote: »

GottaBurnEmAll wrote: »

crazyravr wrote: »

Anything cardio related (running / walking or cycling) yes. Very accurate.
Weight lifting... NOT AT ALL.

It depends on device for weighlifting and how you use it. If I use my Fitbit and put it on weighlifting mode while I lift? It's pretty much giving me a burn on par with what standard METS for lifting does.

I'm currently keeping a spreadsheet for my Fitbit because I never did for my current device, and it's surprisingly accurate.

Garmin Vivoactive HR. For the same workout in weight lifting mode, sometimes I will get 300cal estimate and sometimes more than double that. On the bike or running however, very accurate.

I know Fitbit used to be very off for the weightlifting, but then they changed their algorithm to be more realistic. I don't know what Garmin goes by.

Unfortunately, the problem with using heart rate to estimate calories is fundamental. In the current generation of technology (and for any foreseeable future that occurs to me), we don't have any cheaply/easily-measured variable that tracks consistently and reliably with the amount of work (in the physics sense) being done in any/all types of exercise or activity, and it's the work that determines the calories.

These devices use user profile settings (like age, age or true heart rate max, weight, etc.), and measure things like arm movement (accelerometer), distance covered (gps), heart rate (HRM). They then use statistics from research studies and algorithms written by programmers to estimate calories. Some of them use user behavior history to tune the estimates, which is useful, but not the Big Fix.

Because of the statistical underpinnings, and if they use sound algorithms, the devices will be close to correct for average people (however the average was in the underlying statistics, simplifying slightly). They will be less accurate for some people, and quite inaccurate for a very few. That's how statistics work.

Heart rate, in particular, is a pretty terrible proxy for calorie burn . . . it's just that it's one of the better ones available to an affordable wrist-based (or chest belt) device.

This article is older, but it's still a good and accurate resource for understanding some of the limitations.

https://www.myfitnesspal.com/blog/Azdak/view/the-real-facts-about-hrms-and-calories-what-you-need-to-know-before-purchasing-an-hrm-or-using-one-21472

All you can do as a user is let it collect the history, give it a tested HRmax if you have one (don't let it use age estimates if you can avoid it), set things like stride length carefully, keep your weight in its settings up to date, and do any of its self-tests (for alleged VO2max or HR max or whatever) that you're physically capable of doing.

For me it is awfully a matter of choosing the more conservative MFP numbers vs wechat my Garmin calculates.
I don't sync. I manually enter only deliberate exercise.