Calorie burn discrepency
jwills618
Posts: 12 Member
I have been using a chest strap HRM for working out the past few months that pairs with an app on my phone. I've consistently had lower burns (300ish for 45 minute high intensity class) even with my heart rate getting pretty high. I recently got a fitbit blaze and wore it to the same workout. I constantly (every couple of minutes if not more frequently) checked my heart rate on the fitbit compared to what my chest strap was recording and the heart rates were exactly the same or off by a beat or two consistently.
However, the fitbit gave me a calorie burn of 655 and the HRM gave me one of 355! Any recommendations on why they were so different and which I should trust? They both ask for the same stats (gender, height, weight, age).
However, the fitbit gave me a calorie burn of 655 and the HRM gave me one of 355! Any recommendations on why they were so different and which I should trust? They both ask for the same stats (gender, height, weight, age).
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Replies
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They're different guesstimates because they use different algorithms to calculate calories.
Others will disagree with me but in my view, your chest strap HRM is likely the more accurate of the two.
The FitBit is suggesting you're burning something approaching what an elite sportsperson would burn in the same time.1 -
Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.0 -
I noticed that the first week or 2 I had my Fitbit it was calculating my burn really high. Its calmed down a lot so I think it is "learning" you a bit. I would go the conservative route and use the 355 and then test again in a couple of week sand see if they are closer.1
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They're different guesstimates because they use different algorithms to calculate calories.
Others will disagree with me but in my view, your chest strap HRM is likely the more accurate of the two.
The FitBit is suggesting you're burning something approaching what an elite sportsperson would burn in the same time.
But don't you burn less the more efficient and "elite" of an athlete you are as it relates to a specific workout since your heart rate stays lower? I'm definitely not an elite athlete, I have a lot of weight to lose so shouldn't be calorie burn be relatively high?0 -
TheCupcakeCounter wrote: »I noticed that the first week or 2 I had my Fitbit it was calculating my burn really high. Its calmed down a lot so I think it is "learning" you a bit. I would go the conservative route and use the 355 and then test again in a couple of week sand see if they are closer.
That's very helpful, thank you!0 -
NorthCascades wrote: »Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.
Then what's the point?0 -
They're different guesstimates because they use different algorithms to calculate calories.
Others will disagree with me but in my view, your chest strap HRM is likely the more accurate of the two.
The FitBit is suggesting you're burning something approaching what an elite sportsperson would burn in the same time.
But don't you burn less the more efficient and "elite" of an athlete you are as it relates to a specific workout since your heart rate stays lower? I'm definitely not an elite athlete, I have a lot of weight to lose so shouldn't be calorie burn be relatively high?
No not really.
Heart rate and calorie expenditure have a very loose relationship at best. Your calorie expenditure comes from the power you produce not the number of heartbeats to produce that power.
I've seen three people producing the same power at 130, 150 & 190 beats per minutes. Their calorie output would be virtually the same.
As you get fitter you have a choice:- Do the same level of exercise and it feels easier, heart rate may be lower, calorie burn will be the same.
- Use your extra fitness to go further/faster/harder and burn more calories.
Being heavier simply means that for the same exercise as a lighter person you will burn more calories doing a weight bearing exercise.
So consider me and my 20% heavier boss walking up stairs he will burn 20% more for each floor climbed. But because I'm fitter I could continue to the top of our office block (14 floors) while he is still gasping for air on floor five.4 -
They're different guesstimates because they use different algorithms to calculate calories.
Others will disagree with me but in my view, your chest strap HRM is likely the more accurate of the two.
The FitBit is suggesting you're burning something approaching what an elite sportsperson would burn in the same time.
But don't you burn less the more efficient and "elite" of an athlete you are as it relates to a specific workout since your heart rate stays lower? I'm definitely not an elite athlete, I have a lot of weight to lose so shouldn't be calorie burn be relatively high?
No not really.
Heart rate and calorie expenditure have a very loose relationship at best. Your calorie expenditure comes from the power you produce not the number of heartbeats to produce that power.
I've seen three people producing the same power at 130, 150 & 190 beats per minutes. Their calorie output would be virtually the same.
As you get fitter you have a choice:- Do the same level of exercise and it feels easier, heart rate may be lower, calorie burn will be the same.
- Use your extra fitness to go further/faster/harder and burn more calories.
Being heavier simply means that for the same exercise as a lighter person you will burn more calories doing a weight bearing exercise.
So consider me and my 20% heavier boss walking up stairs he will burn 20% more for each floor climbed. But because I'm fitter I could continue to the top of our office block (14 floors) while he is still gasping for air on floor five.
Interesting, thank you for your response!0 -
NorthCascades wrote: »Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.
Then what's the point?
Of what?0 -
They're different guesstimates because they use different algorithms to calculate calories.
Others will disagree with me but in my view, your chest strap HRM is likely the more accurate of the two.
The FitBit is suggesting you're burning something approaching what an elite sportsperson would burn in the same time.
But don't you burn less the more efficient and "elite" of an athlete you are as it relates to a specific workout since your heart rate stays lower? I'm definitely not an elite athlete, I have a lot of weight to lose so shouldn't be calorie burn be relatively high?
@sijomial beat me to it and probably answered it better than I could.1 -
NorthCascades wrote: »NorthCascades wrote: »Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.
Then what's the point?
Of what?
Any sort of heart rate/calorie tracking if they're all "wrong" and guessing wildly.0 -
NorthCascades wrote: »NorthCascades wrote: »Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.
Then what's the point?
Of what?
Any sort of heart rate/calorie tracking if they're all "wrong" and guessing wildly.
Whilst they're all over the place when it comes to calorie burn guesstimations, if you just look at heart rate then they're useful for motivation in real time and if they record workouts, you can look at trends.
You can also look at things like how long it takes you to recover and what your resting heart rate is.
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NorthCascades wrote: »NorthCascades wrote: »Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.
Then what's the point?
Of what?
Any sort of heart rate/calorie tracking if they're all "wrong" and guessing wildly.
What kind of exercise are you doing?0 -
My simple answer - when in doubt, go with the lower number.1
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You've been using the lower number for months now. Are you losing at the rate you expect or faster? If you are losing properly, stick with that number. Too fast? go with the higher number. You have plenty of data if you track diligently.1
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I have been using a chest strap HRM for working out the past few months that pairs with an app on my phone. I've consistently had lower burns (300ish for 45 minute high intensity class) even with my heart rate getting pretty high. I recently got a fitbit blaze and wore it to the same workout. I constantly (every couple of minutes if not more frequently) checked my heart rate on the fitbit compared to what my chest strap was recording and the heart rates were exactly the same or off by a beat or two consistently.
However, the fitbit gave me a calorie burn of 655 and the HRM gave me one of 355! Any recommendations on why they were so different and which I should trust? They both ask for the same stats (gender, height, weight, age).
Fitbit's calorie calculations are based on how much it moves and how intensely. That means if your exercise program has you arm swinging around a lot in a way that the fitbit detects, it will push the calories higher. The HRM is based on a rather tenuous relationship between HR and calories burned which is usually only accurate for steady state cardio (Not intervals, not weights, and not a whole host of other things). In this case, assuming your information (height, age, sex, weight) are correct and the same in both of them, I would lean toward the HRM. Of course that is not knowing what the activity actually is.0 -
NorthCascades wrote: »NorthCascades wrote: »Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.
Then what's the point?
Of what?
Any sort of heart rate/calorie tracking if they're all "wrong" and guessing wildly.
There are not always "guessing wildly" In fact the term "guessing" would be a wild misrepresentation. The calorie burns are based on studies of actual people. Then they take that information, and apply it the larger population. Since even two people of exactly the same height, weight, sex, and age do not burn calories exactly the same, the numbers are not going to be precise. Then there are confounding factors like does the device and the studies it bases its numbers on work well for a particular activity. For example a fitbit (non-HR model) stinks for cycling, but a HRM would work better, and a power meter even better. Using the wrong tool for the job will result in less than ideal results. As stated, fitbits seems to have a breaking in period (at least according to those who use them) where the numbers are off, so maybe that is the issue. Generally, from the people I know who have fitbits and have used them for a significant period of time, they are pretty close overall for what they are designed to do, that is calculate total daily energy expenditure. HRMs seem to work fairly well for steady state cardio, but the longer you go the more drift upward you HR will have messing the result up slightly. Basically, both tools will give you are better idea than a guess, but not the sort of precision you might think you need, but it is still far better than guessing.0 -
rileysowner wrote: »NorthCascades wrote: »NorthCascades wrote: »Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.
Then what's the point?
Of what?
Any sort of heart rate/calorie tracking if they're all "wrong" and guessing wildly.
There are not always "guessing wildly" In fact the term "guessing" would be a wild misrepresentation. The calorie burns are based on studies of actual people. Then they take that information, and apply it the larger population. Since even two people of exactly the same height, weight, sex, and age do not burn calories exactly the same, the numbers are not going to be precise. Then there are confounding factors like does the device and the studies it bases its numbers on work well for a particular activity. For example a fitbit (non-HR model) stinks for cycling, but a HRM would work better, and a power meter even better. Using the wrong tool for the job will result in less than ideal results. As stated, fitbits seems to have a breaking in period (at least according to those who use them) where the numbers are off, so maybe that is the issue. Generally, from the people I know who have fitbits and have used them for a significant period of time, they are pretty close overall for what they are designed to do, that is calculate total daily energy expenditure. HRMs seem to work fairly well for steady state cardio, but the longer you go the more drift upward you HR will have messing the result up slightly. Basically, both tools will give you are better idea than a guess, but not the sort of precision you might think you need, but it is still far better than guessing.
Guessing wasn't my term, I was quoting a other response
but thank you for the response! 0 -
NorthCascades wrote: »NorthCascades wrote: »NorthCascades wrote: »Ask two different people a question that's a matter of opinion, and you're likely to get two different answers. Instead of people, you can ask computer devices that were programmed by different people, and you'll still get different answers. You can roll some dice and they won't agree either.
Heart rate isn't some kind of secret that unlocks calories. If it was, they'd agree. But it's not, so they have different ways of interpreting the data and guessing, often wildly.
Then what's the point?
Of what?
Any sort of heart rate/calorie tracking if they're all "wrong" and guessing wildly.
What kind of exercise are you doing?
It's a group training class most of the time. Similar to Orange theory fitness where it's a mix of treadmill work, rowing and various strength training0 -
rileysowner wrote: »I have been using a chest strap HRM for working out the past few months that pairs with an app on my phone. I've consistently had lower burns (300ish for 45 minute high intensity class) even with my heart rate getting pretty high. I recently got a fitbit blaze and wore it to the same workout. I constantly (every couple of minutes if not more frequently) checked my heart rate on the fitbit compared to what my chest strap was recording and the heart rates were exactly the same or off by a beat or two consistently.
However, the fitbit gave me a calorie burn of 655 and the HRM gave me one of 355! Any recommendations on why they were so different and which I should trust? They both ask for the same stats (gender, height, weight, age).
Fitbit's calorie calculations are based on how much it moves and how intensely. That means if your exercise program has you arm swinging around a lot in a way that the fitbit detects, it will push the calories higher. The HRM is based on a rather tenuous relationship between HR and calories burned which is usually only accurate for steady state cardio (Not intervals, not weights, and not a whole host of other things). In this case, assuming your information (height, age, sex, weight) are correct and the same in both of them, I would lean toward the HRM. Of course that is not knowing what the activity actually is.
Makes sense, thanks!0 -
You've been using the lower number for months now. Are you losing at the rate you expect or faster? If you are losing properly, stick with that number. Too fast? go with the higher number. You have plenty of data if you track diligently.
That's a great point. I've been losing about the rate I expected so the lower number probably makes the most sense to stick with. Thanks!0 -
Perfect example of how different the algorithms can be between devices: I did a 12.2 mile mountain bike ride today (a little over an hour). I was wearing my Apple Watch and using a Garmin Edge 520 bike computer mounted on my bicycle. Both were synced to my HRM strap (no power meter on the bike).
At the end of the ride, the Apple Watch calculated my average speed as 11.0 mph, the Garmin had it at 11.1 mph; both had my average HR at 123 bpm. Garmin showed the distance as 12.23 mi., Apple Watch said 12.21 mi.
So everything was almost identical between the two as far as workout stats. What did they say about the calorie burn? The Apple Watch said I burned 446 calories, the Garmin said I burned 844. Quite a difference - almost 50%.0
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