Charge 5 - weightlifting / gym kcal counter

[FMXHONDACR]

Could someone tell me how the app compute the total kcal burn in a weightlifting/gym workout?

I had my Charge 5 on my wrist for less than 36hours but today in a 2h 15min training it says I burned over 1000 kcalories... I doubt...

PS: I started the activity when I started the first rep ... and I stopped the activity when I finished the last rep (no stop-start during breaks).

Did I do something wrong?

[Wibby]

Did you tell it you were doing Weights? The arm movements could be confusing if you didn't.  It seems to measure calories burned in conjunction with your heart rate as well as movement.  That kind of calorie burn could possibly happen if you were training vigorously as that's quite a long session.  I only burn about 320 on an hourly Body Pump session (it certainly feels like more though).  It all depends on your resting heart rate on that day too.

Pressing start at the beginning and stop at the end is the right thing to do.

[FMXHONDACR]

Yes, the activity was "PESI" (I'm Italian and "pesi" = "weights")

I don't think in a 2:15 h gym activity (chest day) I could burn that many calories ...

of course i mixed up a bit the recovery time... from 30 sec to 3 min...

changing n° of reps and weights...

(some sets had 5 reps and incrising weight, short recovery time, untill I can't do 5 reps;

others 5x10 at a fixed weight and 2 min recovery time... as usual the last rep is my limit;

others single rep up to my personal best... 3 min recovery time between each increasing attempt)

BTW... my resting heart rate is 57 and this is my yesterday activity (1019 calories)

I don't think that is possible to burn so much calories in a 2:15h weight activity (using rest between series from 30 sec up to 3 min)

[FMXHONDACR]

Yesterday back weights workout...

... same question...

7 excercise - 5 series - 10 reps each (+ sole series increasing weights to achive my working loads)

workout about 30sec and rest 1 min or a little more

70min activity... 552 cal?!? way too much...

PS: now that I see clearly... it seems that the second chart (calories) is in tune with the first (bpm)

PPS: my resting heart rate yesterday was 58

[Giampi71]

Ciao (I'm Italian as well 😀)

I have a feeling the HR is not correctly measured hence the calories are off. It has been proven often that the HR measured by Fitbit (or any wrist optical sensor) can be very wrong (you might check this video that is excellent). Honestly, I'm sorry to say, if I was into gym training I would have opted for a device capable to link with a chest strap that is way more precise.

[Wibby]

That was great!  Thank you! 

I wonder if it might be more accurate on your ankle for weight-training, always assuming you can get some kind of extender to make the strap long enough.  I found it really interesting that it was underestimating the peaks (I expected it to overestimate).

[FMXHONDACR]

---

@Giampi71 wrote:

Ciao (I'm Italian as well 😀)

I have a feeling the HR is not correctly measured hence the calories are off. It has been proven often that the HR measured by Fitbit (or any wrist optical sensor) can be very wrong (you might check this video that is excellent). Honestly, I'm sorry to say, if I was into gym training I would have opted for a device capable to link with a chest strap that is way more precise.

---

CIAO 😀 Thank you for the video!

I know that my Charge 5 is only a fitband and I don't pretend maximum accuracy... but at min 15:50 I hear: "indicating the charge 5 is indicating too low heart rate" ... so (if I'm not wrong) my Charge 5 should underestimate bpm and also calories... but I doubt it's underestimating cals! I suppose it's overestimating this value.

The point it's the algoritm used in calories count...

BTW... I'm only curious and I don't need a calories counting device when I'm dooing gym training.

PS: in the Italian section of this community a moderator sudgested to restart my fitbit (if this could help) or asking the same question to Fitbit Customer Service online or chat.

PPS: I have small ankle and I technically could wear my band to the ankle (I tested the device I give as a gift to my girlfriend a week before purchasing mine)

[FMXHONDACR]

Another workout (after restarting my Charge 5 several times... it's fast on reboot).

I think it isn't change anything and calories count are wrong.

Today deadlift 10 reps increasing weight ... to 5 reps increasing even more ... to single reps (today personal best) for the first 35 min

next abs and glutes in several excercises...

70 min ... again more than 500 calories...

... it has no sense at all... it's clear that a male weight workout burns about 200-250 calories/hour (only super trained athletes can burn 450-500 calories/hour ... and I'm not an athlete) ... if I was dooing cardio I agree... it's possible to achive (and maybe excede) the calories stated in this workuts.

What do you think about?