Don't trust calorie burns from apps!
yirara
Posts: 9,993 Member
I can sync my running app with MFP, and the data gets uploaded here. Yesterday I ran a small 4km at approximately a slow 8min/km pace, but a fairly high HR as I'm currently not feeling well.
Using 0.86*weight(kg)*distance(km) gives me 240kcal (net)
Using the METs table I get 216kcal (net)
(I think my actual calorie burn is somewhere inbetween those two)
MFP isn't actually too bad this time. For this speed and duration I got 254kcal
My running app gave me a whopping 419kcal even though I've stored my actual HRmax in there.
Basically, what I wanted to say is: be careful in what apps and wearables give you. MFP might be fairly off at times, but apps can be even more off, and especially if HR data is involved in calculating the burn. Don't use HR to measure calorie burn as there's no connection between both.
Note: 0.86*weight(kg)*distance(km) croughly corresponds to 0.64*weight (lbs)*distance(miles)
Using 0.86*weight(kg)*distance(km) gives me 240kcal (net)
Using the METs table I get 216kcal (net)
(I think my actual calorie burn is somewhere inbetween those two)
MFP isn't actually too bad this time. For this speed and duration I got 254kcal
My running app gave me a whopping 419kcal even though I've stored my actual HRmax in there.
Basically, what I wanted to say is: be careful in what apps and wearables give you. MFP might be fairly off at times, but apps can be even more off, and especially if HR data is involved in calculating the burn. Don't use HR to measure calorie burn as there's no connection between both.
Note: 0.86*weight(kg)*distance(km) croughly corresponds to 0.64*weight (lbs)*distance(miles)
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Replies
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This is what bothers me about wearable HRMs - I see a lot of people recommending them as a more accurate alternative than standard estimates on the likes of MFP, but I don't really buy it. Your heart rate is at best an erratic guide to calorie burn. It's like trying to calculate MPG by looking at the rev counter.
As someone who suffers from anxiety I'm keenly aware that my heart rate bears little relation to my activity. I know some of the more sophisticated devices have ways of getting additional data, but I still don't think they deserve the deference they often get. It's all guessing at the end of the day.1 -
I don't track exercise calories for this exact reason! There is no accurate or reliable way to measure it. I log my weight and calorie intake and then I can calculate what my average TDEE is over the desired period.1
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Ive had good results with a Zephyr HRM. Its a chest strap style monitor, so definitely not a comfortable wearable.
I run it through the app, Sportstracker Pro, on the phone. It ALWAYS records a couple hundred calories different from my Fitbit.0 -
Agree you shouldn't blindly trust them - with a bit of experience and common sense it's not hard to come up with reasonable estimates though. There isn't really a need for exceptional accuracy anyway - consistency is fine.
I know Strava is generally low (for me of course), Garmin is very low (I've even lied about my weight on Garmin to get closer to reality).
HRMs are fine if used appropriately, certainly usable estimates if not empirically accurate. If you know your HR is elevated above normal for you then that's where common sense comes in. I know my calibrated HRM and an expensive power meter equipped training bike are very, very close but also know if I overheat the HRM will massively diverge for example.
Nope this bit isn't true!
There is a connection but it's personal not universal and subject to external influences.Don't use HR to measure calorie burn as there's no connection between both.0 -
CattOfTheGarage wrote: »This is what bothers me about wearable HRMs - I see a lot of people recommending them as a more accurate alternative than standard estimates on the likes of MFP, but I don't really buy it. Your heart rate is at best an erratic guide to calorie burn. It's like trying to calculate MPG by looking at the rev counter.
As someone who suffers from anxiety I'm keenly aware that my heart rate bears little relation to my activity. I know some of the more sophisticated devices have ways of getting additional data, but I still don't think they deserve the deference they often get. It's all guessing at the end of the day.
Exactly! I have thyroid issues, might take asthma medication or run in hot or cold climate. All those things influence your heartrate, yet a higher heart rate doesn't mean you burn more calories. Likewise, if you're unfit and get up from your sofa your heartrate might be more and longer elevated than from a fit person of the same weight. Still you don't burn more calories getting up. And if you happen to have a fairly high maximum heartrate then those HR trackers are completely useless anyway as every little activity might elevate your heartrate just a bit more than of the average person, yet again you don't burn more calories.
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You shouldn't trust any calorie prediction completely, whether it is from mfp, another app or website, or heart rate monitors. They are all estimations, as are the calorie/nutrition counts in food. I find HRM are more accurate but when in doubt I'd suggest going for whichever is the lower of the 2 to avoid over estimating your calories burned.1
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CattOfTheGarage wrote: »I know some of the more sophisticated devices have ways of getting additional data, but I still don't think they deserve the deference they often get. It's all guessing at the end of the day.
Is your bathroom scale guessing what you weigh?2 -
NorthCascades wrote: »CattOfTheGarage wrote: »I know some of the more sophisticated devices have ways of getting additional data, but I still don't thinking they deserve the deference they often get. It's all guessing at the end of the day.
Is your bathroom scale guessing what you weigh?
Not quite; there's only one variablr there (downward force) and it's measuring that variable directly. It is still not fully accurate, because of calibration issues, but I would not call it a guess - it's measuring what it claims to measure, to a certain degree of accuracy which may or may not be acceptable.
HRMs, on the other hand, claim to calculate how much energy your body is using over a period of time, but that can't be measured directly (except by sealing you in a chamber and measuring your respiration). So what the monitor is actually doing is measuring a different variable - heart rate. Now, you can estimate calorie burn from heart rate as long as you also have several other variables such as cardiac stroke volume, how much oxygen is in the blood and so on. But you simply don't have that data, and you can't get it. So what does the machine do? It puts in an estimate here, a fudge factor there, a few small bodges and what you end up with, to my mind, no longer even qualifies as an estimate. It's an educated guess. And one which depends on the understanding and skill of the user to stop it being completely thrown off by, for example, going for a job interview, or having sex.
I'm not saying HRMs aren't a useful tool, but they're a long way short of what they claim to be, and I am sure they confuse and discourage a lot of people who take them at face value, eat accordingly and fail to lose weight, or even gain it.
For what it's worth, TDEE is also a guess. Yes, you can tweak it based on your own results but the assumption that your burn is the same from day to day is a very big one. Every method of accounting for calorie burn is somewhere on the line between estimate and wild guess, and that's ok - let's just be aware that that applies to magic watches as much as another method - probably more so3 -
So I have my wrist HRM tagged to MFP. On the treadmill, I also use a chest strap that is not linked to MFP. What's funny is the wrist HRM typically shows about 10-15 less BPM than the chest strap. But the calories burned that goes to MFP is about the same as the chest strap.
I just don't eat all the calories back. Actually, I really don't eat any of them back but will drink half of them back (love my wine and the election results needed scotch).1 -
@CattOfTheGarage
HRMs don't claim to measure how much energy your body uses, they measure how fast your heart is beating. That's why they're heart monitors not calorie monitors.
But why are we talking about HRMs? You said "more sophisticated devices" and additional data. And you said that after dismissing HRMs. So I thought you were talking about other devices.CattOfTheGarage wrote: »Every method of accounting for calorie burn is somewhere on the line between estimate and wild guess, and that's ok - let's just be aware that that applies to magic watches as much as another method - probably more so
This is false.
For example, to measure how much energy I put into my bike, I use a direct force power meter. If you look at the data, you can see changes in wind speed and direction from the relationship between my speed, elevation, and power output. The power meter has a maximum error of 2 % and calories from watts or Joules has a maximum error of 5 %. The technology is much like a bathroom scale which we both agreed is a direct measurement and not an estimate.1 -
I've got a Garmin VivoActive. I've been wearing it for the last six months. I have it synced with MFP, have my activity level set to sedentary and I eat back, pretty much, all of my daily activity calories as well as any exercise calories that the VivoActive figures in for when I'm jogging. I've lost 105lbs since last October and when I was eating at my defecit, never gained gained any weight during any weigh-ins.
I think your mileage my vary, depending on which device you use. Some overestimate, some underestimate and some tend to be pretty on, from reading other people's stories on here. I'd say you just have to give a device a whirl for a month to see how accurate it is, for you. I've been in maintence now for about 2-3 months and still eat back all of my extra calories as well as calculated exercise calories and I'm still holding steady at the same weight.1 -
I've got a Garmin VivoActive. I've been wearing it for the last six months. I have it synced with MFP, have my activity level set to sedentary and I eat back, pretty much, all of my daily activity calories as well as any exercise calories that the VivoActive figures in for when I'm jogging. I've lost 105lbs since last October and when I was eating at my defecit, never gained gained any weight during any weigh-ins.
I think your mileage my vary, depending on which device you use. Some overestimate, some underestimate and some tend to be pretty on, from reading other people's stories on here. I'd say you just have to give a device a whirl for a month to see how accurate it is, for you. I've been in maintence now for about 2-3 months and still eat back all of my extra calories as well as calculated exercise calories and I'm still holding steady at the same weight.
I've been thinking about getting this one too I just need something to somewhat guesstimate for me and it's good to see about where your working at!!! I was hoping to see someone had something like this and was happy0 -
I've had pretty good luck with a Polar H7 paired with Endomondo on my iPhone. I know I should probably leave about 10-15% of the exercise calories at the end of the day to keep from going over maintenance, but honestly even doing that I'm slowly losing weight still. Not by much, but in recomp I've lost an average of about .25 to .5lb a week. So I could probably eat back 90-95% of the calories Endomondo is telling me I burn. But, that's me. Everyone is different. I happen to be 6'2" tall so someone with less height may burn less with the same heart rates I see during my exercise. I keep my height/weight/age stats updated in my app and it seems to keep accurate results within reason.
But... as the OP said.. not all are that way. I can use Endomondo in the mornings for a 510 calorie burn (that's my goal I set) on my M5. When I'm finished about 35 minutes later the M5 itself says I've burned 600 or more calories. That is why I don't use its app to connect to MFP, it would be over estimating because it bases its burns on RPM and resistance settings not by HR.
So my suggestion is make sure you're setting up your height/weight/age in your app/device, and if it doesn't have that setting then find a different app. It makes a big difference, and the app should be calculating different burn rates based on your data, and that includes heart rates.0 -
NorthCascades wrote: »@CattOfTheGarage
HRMs don't claim to measure how much energy your body uses, they measure how fast your heart is beating. That's why they're heart monitors not calorie monitors.
But why are we talking about HRMs? You said "more sophisticated devices" and additional data. And you said that after dismissing HRMs. So I thought you were talking about other devices.CattOfTheGarage wrote: »Every method of accounting for calorie burn is somewhere on the line between estimate and wild guess, and that's ok - let's just be aware that that applies to magic watches as much as another method - probably more so
This is false.
For example, to measure how much energy I put into my bike, I use a direct force power meter. If you look at the data, you can see changes in wind speed and direction from the relationship between my speed, elevation, and power output. The power meter has a maximum error of 2 % and calories from watts or Joules has a maximum error of 5 %. The technology is much like a bathroom scale which we both agreed is a direct measurement and not an estimate.
Yup...
Add to that, it doesn't have to be exact...it has to be good enough...and you have to use some common sense. I used my HRM for steady state cardio to get my "eat back" calories when I was doing MFP...I am fully aware that it wasn't exact, but it was certainly good enough as I had zero problem dropping weight.1 -
I can completely get behind something like a bike-mounted device to measure how much energy is being put into the machine. Similarly, it should be possible to geta really accurate energy burn from something like a treadmill or elliptical, and I'm puzzled by why, according to people's experience on here, those numbers tend not to be accurate. It seems like they should be able to be, because like your bike monitor they are directly measuring the energy you put into the machine.
I should probably clarify that when I talk about "magic watches" and "other devices" I'm talking about the whole family of things you strap onto yourself which infer a calorie burn based on heart rate and send that calorie burn to MFP automatically, which I think is a basically problematic way of doing it. When I said "other data" I was talking about things like heart rhythm, which I believe the more sophisticated ones can use to differentiate between fast pumping without a big burn (eg anxiety) or genuine exertion. But it will always be a tenuous link which the user needs to take with a pinch of salt. That's fine, but it's not how they are marketed.
I also see ambiguity about which monitoring methods include BMR for the period of exercise and which ones are only measuring extra burn due to exercise- I suspect a lot of people who panic because they aren't meeting their goals are unclear on this and end up counting BMR twice during exercise.1 -
I don't understand why people like to say it's impossible to measure how many calories you burn, and state it like that's some kind of law of nature. I think that does everyone a disservice. For starters, it's not true. But if it was true, people don't need to know down to the 1/10th of a calorie how much energy they burned on their evening walk. You can lose weight with ballpark figures as long as the way they're measured is consistent.2
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NorthCascades wrote: »I don't understand why people like to say it's impossible to measure how many calories you burn, and state it like that's some kind of law of nature. I think that does everyone a disservice. For starters, it's not true. But if it was true, people don't need to know down to the 1/10th of a calorie how much energy they burned on their evening walk. You can lose weight with ballpark figures as long as the way they're measured is consistent.
I guess that would depend if the type of activity you do is consistent, too. I wouldn't assume that calculations based on HR are going to be off by the same amount for cycling as they would be for running or rock climbing, even if they are done by the same device.
Not something I have to think about now, but it'd drive me nuts if I exercised the way I used to - every day a different activity so I didn't lose interest in exercising entirely. Especially if I needed to keep my deficit small.0 -
Well of course you'll burn a different number of calories walking slowly versus running or sitting down versus climbing granite cliffs. Measuring tools don't replace common sense.
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Anecdotally I use my watch and chest strap for everything I do, and there is a huge amount of variety there. I eat back what it tells me I burned. I lost all the weight no problem and have stayed within a pound of maintenance since July.
That said, everything (including TDEE) is an estimate, and there is some common sense involved. I tweaked my TDEE very early in maintenance and have had no issues since.
If your GPS doesn't get you to exactly every single place you ever drive do you throw it away and go back to maps? Probably not. Fitness watches aren't perfect, but with some common sense mixed in can be a very valuable tool.2 -
NorthCascades wrote: »Well of course you'll burn a different number of calories walking slowly versus running or sitting down versus climbing granite cliffs. Measuring tools don't replace common sense.
I said the amount the calculations would be off would likely differ - it might be a 20% variance for bicycling and a 40% variance for rock climbing, but only a 10% variance for running, etc. I did not say anything about the number of calories burned - as if you could even compare activities that way with no knowledge of duration or intensity.
I'm a bit in a fog given I had a late night, but I'm not that out of it.0 -
@stealthq
A lot of people think you should enter everything you do in MFP, and then cut its estimate in half. No matter what you did. So if you ran for an hour, take 50 % of the calories MFP thinks you burned; if you walked for an hour, take 50 %, and if you slept for an hour, take 50 % of that.
You're saying this practice doesn't make a lot of sense. I agree with you. I don't understand why everybody doesn't agree with you. What you're saying seems pretty obvious and common sense.
Take a Fitbit for example, especially an old one. It's probably reasonably accurate for walking, because that's what it was programmed for. It has a lot of understanding that's specific to walking. And that doesn't carry over to weight lifting or rock climbing because these are different activities than it's made to estimate, using different muscles and energy systems in the body.0 -
trigden1991 wrote: »I don't track exercise calories for this exact reason! There is no accurate or reliable way to measure it.
Power Meters are pretty dAm close....
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AFELLER1744 wrote: »I've got a Garmin VivoActive. I've been wearing it for the last six months. I have it synced with MFP, have my activity level set to sedentary and I eat back, pretty much, all of my daily activity calories as well as any exercise calories that the VivoActive figures in for when I'm jogging. I've lost 105lbs since last October and when I was eating at my defecit, never gained gained any weight during any weigh-ins.
I think your mileage my vary, depending on which device you use. Some overestimate, some underestimate and some tend to be pretty on, from reading other people's stories on here. I'd say you just have to give a device a whirl for a month to see how accurate it is, for you. I've been in maintence now for about 2-3 months and still eat back all of my extra calories as well as calculated exercise calories and I'm still holding steady at the same weight.
I've been thinking about getting this one too I just need something to somewhat guesstimate for me and it's good to see about where your working at!!! I was hoping to see someone had something like this and was happy
It's truly a great fitness tracker. Like I said, I eat back, pretty much, everything it gives me and I've never gained weight. I specifically chose this one because of the GPS. Nothing will be more accurate than a step counter as well as a GPS that knows how long it took you to get from point A to B during a jog.0
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