Calorie adjustment way over estimated?

srecupid

Just got my charge HR and this is my very first full day wearing it. I am 5"10 170ish male and put it 11k steps today. It's awarded me about 700 extra calories. Before I had a garmin device and it would only reward me about 200 or so calories on a regular day but, that didn't factor in the heart rate. I'm not sure why i even bought the thing if i can't trust it. Has it been accurate for you guys?

Christine_72

Sorry can't help you, but I will never buy a HR monitor device. My gut feeling tells me they're dodgy. I'll stick to my Alta, especially because the only exercise I do is walking.

NancyN795

I just did a test where I logged my food as accurately as I could for the month of May and then compared my actual weight loss to my expected weight loss. (Normally, this would be easy because Fitbit provides average intake and average calorie burn for the last 30 days on your profile page, but there's a bug, so I had to export my Fitbit data to a spreadsheet to get it.) Anyway, for me, it seems like my Fitbit currently overestimates my daily burn by about 6%. Now, my food logging definitely had some holes in it (a few days or meals when I had little to no ability to accurately estimate my calorie intake), so that is probably part of the error.

Anyway, for some lucky people it is right on, for others it is high, for a few it is low. The only way to tell is to test it yourself. But, it can't be for just a few days. The minimum has got to be a month.

I have a Charge HR. I find the heart rate data to be reasonably comparable to my chest strap HRM and to spot checks of my heart rate. I wouldn't rely on it as a medical device, and I don't know if it increases the accuracy of Fitbit's calorie burn estimate, but I like having the HRM data.

heybales

srecupid wrote: »

Just got my charge HR and this is my very first full day wearing it. I am 5"10 170ish male and put it 11k steps today. It's awarded me about 700 extra calories. Before I had a garmin device and it would only reward me about 200 or so calories on a regular day but, that didn't factor in the heart rate. I'm not sure why i even bought the thing if i can't trust it. Has it been accurate for you guys?

The 1st week or two will have the HR-based formula for calorie burn adjusting to you and your workouts, and resting HR.

You may have had some times today where it slipped into HR-based calorie burn when it wasn't really exercise level to warrant using that - that'll be corrected as it sees your resting HR and frequency of workouts and decides what your HR normally is for start of exercise.

You got any Activity records it created for you on Fitbit site - those would be when it used HR-based calorie burn.

It could also be that your default stride length is way off - and since your non-exercise time moving is based on steps and distance and mass - that foundation of stride length being off could badly effect the daily burn.

Additionally, it could have seen a bunch of extra steps related to something - so review your daily 5 min graph for big step times and confirm that at least seem realistic to reality.
Step counts could still be off too though.

Sensitivity settings can help those issues - manually entered stride length for that issue - time for the HR-based calorie burn issue.

Was the Garmin synced with MFP, and you had the same activity level on MFP?

RunRachelleRun

I found my Charge HR to be fairly inaccurate compared to my Garmin. Here is a screen shot of a run where I wore both. It took me a while to get my stride to match. Usually the heart rate during workouts was much lower than that given by my Polar or Garmin chest strap monitors. I think for everyday non-activity heart rate, it was close. There was a definite lag during workouts, as much as 20 minutes until it would start to match the Garmin. My max hr almost always was similar, but the avg hr was often 10-15 beats lower. This run was fairly close in the calories burn, which happened occasionally. Sometimes Fitbit gave me double what Garmin would for even though the hr was closer (on May 14th I did an easy 548 ft elevation 2-hour hike: Garmin gave me 495 calories for 120 avg hr; Fitbit gave me 931 calories for 119 avg hr).

Since getting a Fitbit last spring, my weight loss has been minimal. Prior to that, I was using MFPs suggestion plus Garmin's exercise calories. I did much better with that. It has taken me a while (okay, a year) to accept that Fitbit has been overestimating my calorie burn by quite a bit. I have just passed my Charge HR along to my husband who likes it for the daily step counting and mileage guesstimation (he's a postie). I went back to my One for tracking steps in daily activity (just as encouragement to get off my butt and move more) but have unlinked it from MFP.

I have a low resting heart rate but a high working heart rate, so perhaps this makes me a special snowflake and confuses Fitbit. It may work better for those with average working heart rate zones. If they allowed me to set my zones like the Garmin does, maybe it would have been more accurate, or maybe not.

heybales

The zones wouldn't have made a difference - what each is going for as HRmax would have.

Garmin on past devices used a different method, besides being manually setable if desired - Fitbit is unknown but likely the old 220-age favorite.

Fitbit since it knows your restingHR though does seem to try to figure out when the exercise level starts, whereas Garmin is basing it off 90 if using the Firstbeat algorithms.

That is pretty bad difference in avgHR there - and that wasn't even some interval type workout.

RunRachelleRun

I set Garmin zones and max (200) to my tested lab results. FitBit (I assume) uses age max of 178. I think it is assuming hard exercise too early. I tried changing age and height but that brought new issues.

I have a ForeRunner 310xt. Does it fall under the past devices you mention? Are the new ones better or worse in your opinion?

lauraesh0384

I can say that my resting HR is accurate though I'm not sure about my exercise based HR. I tested the HR reading on my Charge HR against a medical grade monitor at work and it was only off by 1 bpm. To me that's pretty darn accurate. Not to mention I've been eating about 90% of my exercise calories and my weight loss has been consistent.

heybales

RunRachelleRun wrote: »

I set Garmin zones and max (200) to my tested lab results. FitBit (I assume) uses age max of 178. I think it is assuming hard exercise too early. I tried changing age and height but that brought new issues.

I have a ForeRunner 310xt. Does it fall under the past devices you mention? Are the new ones better or worse in your opinion?

The 310XT does indeed use the Firstbeat algorithms.

I haven't reviewed their newer device manuals to see if they say something about under license to them still. It used to be Garmin would make the claim I guess to impress, some other devices though that still used it basically hid the fact for whatever reason.

It is still estimating your VO2max based on observed level of weekly workout time/frequency, and that option of lifetime athlete.

So if you have a decent amount of workouts without the Garmin, it'll be calculating lower VO2max than potential.

I have that one too, got into the research of Firstbeat, and the research study they used as basis.

If curious, on my profile page, the Weight Loss spreadsheet has a Garmin HRM tab that shows what is happening.

The research study that Polar uses actually had better accuracy against measured VO2max, that's the one on the HRM tab.

If you know your figure - you can see what each would calculate to compare.

RunRachelleRun

Thanks! I'll check out your spreadsheet now

RunRachelleRun

Way cool spreadsheet @heybales. The hr zones are very close once I entered my tested LT, which is the only time I've seen anywhere near the ones I got during my test. According to your spreadsheet, Garmin and Polar are both very close in estimating calories burned (3-6 calories), which is good enough for me. Thanks again!