Vastly different calorie estimates for workouts

[dr.girlfriend]

Sorry if this is a silly question, I'm relatively new to exercising.

I wear a Fitbit, and I also have my own treadmill.  Both have my height, weight, etc. info programmed in.

I actually keep my left hand on the handle when I treadmill, because I have an issue with the brachial nerve on that side.  So, at the end of my time on the treadmill I manually enter into my Fitbit the start time, duration, and mileage of my walk and make sure the pace matches what the treadmill said.

I do five miles in about 70 minutes, a mile each at 4.1, 4.2, 4.3, 4.4, and 4.5.  The treadmill says my workout is 682 calories.  My Fitbit says it's 282 calories.

Any idea why the huge difference?  Which one seems closer to correct?  If it helps I'm 5'0", 140 pounds, age 48.  My average bpm for the workout is usually mid-120s.

[minzy]

I am no expert and don’t even have a Fitbit or any other legit trackers, so feel free to ignore me. I loosely assume running burns about 100 cal/mile, so would guess you’d be closer to 500 cal.

This is just a random thing I googled but plugging in your stats here gives you 467, which seems fairly reasonable?
caloriesburnedhq.com/calories-burned-running/

[Deleted]

I am very close to your size, am very active, and also wear a fitbit. You are walking at a pretty fast pace. No way are you only burning 270 calories, but i also think 680 is a bit high. Based on my own experience, i think Minzys estimates of ~500 are probably pretty close.

[dr.girlfriend]

May 10, 2021 22:31:47 GMT -5 @peep said:

I am very close to your size, am very active, and also wear a fitbit. You are walking at a pretty fast pace. No way are you only burning 270 calories, but i also think 680 is a bit high. Based on my own experience, i think Minzys estimates of ~500 are probably pretty close.

Thanks.  Yes, I probably should have specified, I have short little legs and that top pace is as fast as I can walk without having to jog.  Have you found that your Fitbit seems to underestimate, or would it give you a calorie estimate of about 500 for that level of activity?

[Deleted]

May 11, 2021 8:58:24 GMT -5 dr.girlfriend said:

May 10, 2021 22:31:47 GMT -5 @peep said:

I am very close to your size, am very active, and also wear a fitbit. You are walking at a pretty fast pace. No way are you only burning 270 calories, but i also think 680 is a bit high. Based on my own experience, i think Minzys estimates of ~500 are probably pretty close.

Thanks.  Yes, I probably should have specified, I have short little legs and that top pace is as fast as I can walk without having to jog.  Have you found that your Fitbit seems to underestimate, or would it give you a calorie estimate of about 500 for that level of activity?

Lol, that is top speed for me, too, without running. My Fitbit seems to overestimate calories burned walking. I dont walk a lot, but i can extrapolate from what i do that it would probably say 500-600 calories for 5 miles at that pace. That is a fast pace for us short folks! I would probanly use 400-450 as my calorie estimate.

[dr.girlfriend]

Also, just for fun/motivation, I looked back through my threads and found the one where I was initially seeking newbie treadmill advice about a year ago. At that time 3.7 mph was "miserable" for me, so I guess I've improved a lot! :-D

[Wines Not Whines]

I agree with the others that 100 calories/mile is a good estimate. I know from experience that I burn around 80 calories per mile, whether I’m walking or running, but I’ve been running for a while, so I’ve gotten more efficient over time. Treadmills usually over-estimate. My Garmin watch is pretty accurate, but it also measures my HR, so it takes that into account. Does your FitBit measure HR? You could try wearing it on your right hand and see if it measures more accurately than when you do a manual entry. But either way, I think 100 cal/mile is going to be close.

[breezy8407]

I'm around 80-90 calories a mile when I run, too.

I have a Garmin and use a chest HR strap, so even though they are all estimates its my standard to check to make sure I am working hard enough or staying where I want to be.

[dr.girlfriend]

Thanks, everyone. Yes, Wines Not Whines, the Fitbit does take my heart rate, which is why I'm confused as to it not being the more accurate of the two once I adjust the distance, which is always a very significant underestimate because I don't swing my left arm.  Here's my workout today, for example:

[Wines Not Whines]

That’s interesting. The HR measurement seems fairly accurate, too.

[lilypad1126]

Is your fitbit calculating your calories before you adjust your workout for the right distance? What I mean is, do you set it to track your workout, do your workout while holding on (so you aren't swinging your arm), then go in and reset your distance, but it shows calories burned? So it's calculating the calories with the wrong distance?

I ask, b/c if i set my garmin to "indoor walk" when walking on a treadmill, if it doesn't sense my movement, everything basically pauses, including the calorie counting. So at the end, when I look at it, it might show the right time, but everything else it tracks is way off, including calories. Even though the heart rate monitor is, in theory, going the whole time, it never calculates my calories burned accurately. Which I know, b/c I've used the outdoor walk feature plenty and it calculates my calories more accurately on that workout.

[dr.girlfriend]

May 14, 2021 7:27:29 GMT -5 lilypad1126 said:

Is your fitbit calculating your calories before you adjust your workout for the right distance? What I mean is, do you set it to track your workout, do your workout while holding on (so you aren't swinging your arm), then go in and reset your distance, but it shows calories burned? So it's calculating the calories with the wrong distance?

I ask, b/c if i set my garmin to "indoor walk" when walking on a treadmill, if it doesn't sense my movement, everything basically pauses, including the calorie counting. So at the end, when I look at it, it might show the right time, but everything else it tracks is way off, including calories. Even though the heart rate monitor is, in theory, going the whole time, it never calculates my calories burned accurately. Which I know, b/c I've used the outdoor walk feature plenty and it calculates my calories more accurately on that workout.

lilypad1126 , sorry, I just saw this.  

Something is definitely glitchy.  When I end the walk and it estimates 1.2 miles based on the swing of my left arm, it lists the calories as 175.  When I adjust the mileage to 5.0, it increases it, but only to 280-ish. 

BUT, today I noticed that when I adjust the slider for miles from 1 to 5, it jumps up to 600, but then when I adjust the tenths of the miles from .2 to .0 it jumps back down to 280.  So, somehow it thinks 5.2 miles in 70 minutes (1 hour, 9 minutes, 50 seconds to be exact) is 604 calories but 5.0 miles in that same time span is 278 calories.  Given that I usually hit at least 5.1 miles by the time the treadmill stops at the 70-minute mark (I let it go a few seconds over because if not when I repeat the workout it stops a few seconds early and doing 4.99 miles is VERY frustrating to me!) I can't imagine that extra 10th of a mile would make all the difference.  Something is definitely wrong with their math.  Posting screenshots in case that helps someone figure out what's going on.



d