# Calorie Count Algorithm



## Edge705 (14 Sep 2011)

Hi all trying to make sense of the new Garmin 800 I have
Take a look at this http://connect.garmin.com/activity/108924320

Then this http://connect.garmin.com/activity/114394980

This is my commute home from work I do this approx 4 times a week pay particular attention to the calories burnt on each ride

The first link is using the garmin edge 705

The second link is using the the edge 800 which I just upgraded to

Heck of a difference the user profiles in the garmin are exactly the same ie 47 year old occasional cyclist which one do you rekon would be the most acurate ? I would say 176-180 is at the top of my HR bracket ie: im blowing out of my backside 160-166 is normal for my commute rides anything in the 150's is more than comfortable for me.

Im just trying to work out what would be more applicable I believe its not either and more like around 800 I was told the garmins have the best HR algorithm in fact Polar I believe have been trying to emulate Garmin's algorithm for years


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## VamP (15 Sep 2011)

The second is a lot closer to reality.

I do similar distance regularly, same sort of speed, same sort of elevation and assume that i burn cca 500 calories per hour, so about 450 calories on that. There is no way you wil be burning 800, never mind the edge 705 number.




Edge705 said:


> Hi all trying to make sense of the new Garmin 800 I have
> Take a look at this http://connect.garmi...ivity/108924320
> 
> Then this http://connect.garmi...ivity/114394980
> ...


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## Edge705 (15 Sep 2011)

VamP said:


> The second is a lot closer to reality.
> 
> I do similar distance regularly, same sort of speed, same sort of elevation and assume that i burn cca 500 calories per hour, so about 450 calories on that. There is no way you wil be burning 800, never mind the edge 705 number.



I agree and thanks for that its now put my mind at ease now

Cheers


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## HLaB (15 Sep 2011)

That 705 reading looks way too much, looking at my records with an older 305 garmin suggests I burn 750-850 calories, I could be wrong but I think time is the major dominating factor I take a few minutes longer than you , my routes are hillier and garmins are notorious for over prediction; if I look at a 47-48min ride its around 650 for me.


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## jowwy (15 Sep 2011)

I've since switched to a heart rate monitor to try and gauge better my calories burnt - cause some sections of my commute are very hilly and i work a lot harder physically, calories burnt shouldnt be calculated on miles v's time

IMO


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## jowwy (15 Sep 2011)

Edge705 said:


> Hi all trying to make sense of the new Garmin 800 I have
> Take a look at this http://connect.garmi...ivity/108924320
> 
> Then this http://connect.garmi...ivity/114394980
> ...



On looking at both of your links the second link as you only climbing 377ft - compared to nearly 500ft on the first one, makes a hell of a difference on calories burnt. again its only my opinion.


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## Edge705 (15 Sep 2011)

jowwy said:


> On looking at both of your links the second link as you only climbing 377ft - compared to nearly 500ft on the first one, makes a hell of a difference on calories burnt. again its only my opinion.



yes strange but its the same route always I dont deviate

take a look at this one http://connect.garmin.com/activity/108924358 again similar climbing but high calorie count which i know know is more improbable than probable

Incidentaly I always wear a heart rate monitor but Im gonna stick with a 600 count for a 48 minute ride just like everyone else seems to be pointing to - 

I should point out half the time Ive got a 14LB laptop in my back sack would that make a difference?


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## jowwy (15 Sep 2011)

For me i would go with what the heart rate monitor says - at least that is telling how hard ur heart is working during the ride and not just a tme v's distance calculation 

everybodys body works differently and 600 calories an hour is just an average value, thats worked out by using a standard calculation. I just rode home from work its 12.6miles with a 1000ft of climbing, did it in 63 minutes and my heart rate monitor said i burnt 1100 calories, i'm just under 15st and 5ft 9 and not very fit at all but getting there, so my heart and lungs are working overtime to get me through the commute. The harder you work, the more calories u burn. if you just slow trudge it then calories burnt will be lower.

again its just my opinion, but since starting cycling 6months ago, i have listened to my heart rate monitor and lost just over 4 stone in weight, go figure.


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## amaferanga (15 Sep 2011)

jowwy said:


> For me i would go with what the heart rate monitor says - at least that is telling how hard ur heart is working during the ride and not just a tme v's distance calculation
> 
> everybodys body works differently and 600 calories an hour is just an average value, thats worked out by using a standard calculation. I just rode home from work its 12.6miles with a 1000ft of climbing, did it in 63 minutes and my heart rate monitor said i burnt 1100 calories, i'm just under 15st and 5ft 9 and not very fit at all but getting there, so my heart and lungs are working overtime to get me through the commute. The harder you work, the more calories u burn. if you just slow trudge it then calories burnt will be lower.
> 
> again its just my opinion, but since starting cycling 6months ago, i have listened to my heart rate monitor and lost just over 4 stone in weight, go figure.



You can't work out calories from HR. You can make an educated guess, but its no better than that. No way do you burn 1100 kcal in a little over and hour riding at 12.6mph! 

I've got what is probably the most reliable calorie counter on my bike - a power meter. The calories you burn is determined mostly by the Watts you generate. Two riders could have very different HR for the same Watts, hence why calorie estimates on HR monitors or Garmins use various algorithms to try to make a best guess. But the simple fact is you can't guess the power output for a given ride and therefore you can't really make a good guess for calories burnt. My Garmins always significantly underestimate calories burnt, I guess because I'm a slow beater (i.e. I can generate Watts at lower HR than most). For some folk Garmins massively overestimate. Unfortunately without an independent means of calculating calories you'll never know for sure which group you fall into.

HR doesn't actually tell you how hard you're working (how many Watts you're putting out). It just tells you how fast your heart is beating.

But I will repeat - no way do you burn 1100 calories in just over an hour riding at 12.6mph.


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## VamP (16 Sep 2011)

amaferanga said:


> You can't work out calories from HR. You can make an educated guess, but its no better than that. No way do you burn 1100 kcal in a little over and hour riding at 12.6mph!
> 
> I've got what is probably the most reliable calorie counter on my bike - a power meter. The calories you burn is determined mostly by the Watts you generate. Two riders could have very different HR for the same Watts, hence why calorie estimates on HR monitors or Garmins use various algorithms to try to make a best guess. But the simple fact is you can't guess the power output for a given ride and therefore you can't really make a good guess for calories burnt. My Garmins always significantly underestimate calories burnt, I guess because I'm a slow beater (i.e. I can generate Watts at lower HR than most). For some folk Garmins massively overestimate. Unfortunately without an independent means of calculating calories you'll never know for sure which group you fall into.
> 
> ...



+1

HR monitor's are virtually useless as predictors of calorific consumption. You're better off working from average speed, and making a hill adjustment.

As amaferanga says, there is no way you can burn even half of 1100 calories in an hour at 12 miles an hour.


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## jowwy (16 Sep 2011)

Like i said its just my own personal opinion - but i'm losing the weight and adjusting my calorie after rides to take into account what my heart rate monitor tells me i have burnt - and the scales don't lie............

i'm not here to get into arguments over who's right or wrong - i'm just givimg my opinion 

http://www.weightlossresources.co.uk

*How many calories will cycling burn?*
Depending on your weight and exertion level cycling will burn off between *75-670 extra calories** in a half-hour cycle session.


* 30min Cycling will burn:*

Recreational, 5mph: 75-155kcal
Moderate, 10mph: 190-415kcal
Vigorous, 15mph: 300-670kcal
 If you are keen to use cycling to burn calories and so lose weight, think about it like this…
A half hour daily cycle trip could burn 11 pounds of extra fat in a year. Because the activity is frequent, the weight is likely to stay off – combine it with a change to a healthier calorie-counted diet and weight loss will be even more effective.

_*Extra calories are those you burn on top of the calories you use for basic day-to-day living. Inputting your exercise into your __exercise diary__ will calculate the number of calories you will burn, based on your weight._


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## VamP (16 Sep 2011)

jowwy said:


> *30min Cycling will burn:*
> 
> Recreational, 5mph: 75-155kcal
> Moderate, 10mph: 190-415kcal
> Vigorous, 15mph: 300-670kcal



You gotta love the range on offer. I could just about agree with the low numbers. I guess they're covering their asses for people riding grossly inefficient BSOs witht the high numbers.

670 calories in 30 minutes! Tour de France riders don't burn that much.

Glad cycling is working for you and you're losing the weight though, that's what counts at the end of the day. But if you're adjusting by 1100 calories per hour of cycling, then you're burning the difference somewhere else. Which is fine.


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## jowwy (16 Sep 2011)

Thats because tdf riders are fitter, stronger and lighter than the average overweight guy on a bike trying to lose weight.

The more unfit and overweight you are the harder your body works to do certain things. Hence the higher calorific burn.


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## dongo (16 Sep 2011)

The Garmin 705 is known for massively over estimating calorie burn. 

There are people who recommend entering your weight as about 60% of actual in order to get a more realistic value.

The 800 is supposed to be better but none of these things can give you any more than a rough estimate.


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## VamP (16 Sep 2011)

jowwy said:


> Thats because tdf riders are fitter, stronger and lighter than the average overweight guy on a bike trying to lose weight.
> 
> *The more unfit and overweight you are the harder your body works to do certain things. Hence the higher calorific burn.
> *



While that is true, the effect is a lot less than you think. And cycling of all sports is towards the least affected end of the spectrum.

I am not sure why you're persevering with this, the information on calorific consumption is easily available out there, and the uselessness of HR monitors, and general tendency of calorie measuring calculators to massively overestimate is well known.


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## jowwy (16 Sep 2011)

And there is also plenty of calorie counting websites out there that u can put weight, speed and time into that will give a decent reading on calories burnt too.

But everything is based on averages and assumptions........and you know what they say when you assume something.

:-)


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## amaferanga (16 Sep 2011)

jowwy said:


> Thats because tdf riders are fitter, stronger and lighter than the average overweight guy on a bike trying to lose weight.
> 
> The more unfit and overweight you are the harder your body works to do certain things. Hence the higher calorific burn.





It's very simple - for cycling the calories you burn is mostly determined by your power output. So even if the fat, unfit cyclist is sweating like a pig, it's very likely their power output is significantly less than that of even an amateur racer. They might feel like they're working harder than the Pro cyclist, but in cycling it's all about the Watts you're putting out.

To give you a bit of perspective on your calories burnt figure....

1100 calories --> 306W power output --> enough power to average ~25mph on a road bike on a flat road. 306W is also a very respectable power average for a pro cyclist on a TDF stage. 306W is not a likely power output for someone averaging only 12.6mph on rolling roads in the UK.

Just because you're overweight doesn't change the fact that calories burnt comes from the energy you use to propel yourself forward and if as an average overweight cyclist you can average 306W for an hour then I suggest you give up your day job and train full time because you're blessed with a talent and a pro contract will be well within your reach.

I'm sure you won't accept this because you've looked at some websites that say otherwise, but please stop perpetuating the wildly optimistic calorie figures.


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## lulubel (17 Sep 2011)

The 705 uses distance/time to calculate calories burned, and the 800 uses your heart rate. Hence the difference.



jowwy said:


> http://www.weightlossresources.co.uk
> 
> *How many calories will cycling burn?*
> Depending on your weight and exertion level cycling will burn off between *75-670 extra calories** in a half-hour cycle session.
> ...



That particular website (which I use because it's very useful for keeping track of calorie consumption) underestimates my cycling calories burned by 150-200 an hour.


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## jowwy (17 Sep 2011)

lulubel said:


> The 705 uses distance/time to calculate calories burned, and the 800 uses your heart rate. Hence the difference.
> 
> 
> 
> That particular website (which I use because it's very useful for keeping track of calorie consumption) underestimates my cycling calories burned by 150-200 an hour.



No it doesnt LULUBEL that site and all the other sites that estimate calorie consumptions including heart rate monitors are absolutely useless because the above members said so!!!!


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## lulubel (17 Sep 2011)

jowwy said:


> No it doesnt LULUBEL that site and all the other sites that estimate calorie consumptions including heart rate monitors are absolutely useless because the above members said so!!!!



Calorie consumption is the amount of calories you consume by eating food. There's no estimate involved, unless you guess your portion sizes. If you weigh everything, you can calculate your calorie consumption accurately.

As for calories *burned*, that's another matter entirely. I'm not aware of any totally accurate way of calculating it (although I suppose it could be done in controlled conditions in a lab with the right equipment) because there are so many variables involved. Experience tells me that my HRM is fairly accurate *for me*.


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## jowwy (17 Sep 2011)

Sorry lulubel burnt is what i meant to say. 

And as for heart rate monitors mine works for me too, hence the 4stone + weight loss.


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## amaferanga (18 Sep 2011)

lulubel said:


> Calorie consumption is the amount of calories you consume by eating food. There's no estimate involved, unless you guess your portion sizes. If you weigh everything, you can calculate your calorie consumption accurately.
> 
> As for calories* burned,* that's another matter entirely. *I'm not aware of any totally accurate way of calculating it *(although I suppose it could be done in controlled conditions in a lab with the right equipment) because there are so many variables involved. Experience tells me that my HRM is fairly accurate* for me.*




A power meter. The only unknown is your efficiency, but this doesn't vary much between individuals and for a given person it changes little if at all with changes in fitness. Certainly should be possible to compute calories burnt to within 10% for anyone.





jowwy said:


> No it doesnt LULUBEL that site and all the other sites that estimate calorie consumptions including heart rate monitors are absolutely useless because the above members said so!!!!




Just because a hundred websites repeat the same bit of information doesn't make it correct. You cannot reliably calculate calories burnt from HR. That is a fact. If it happens to work for you then you're very lucky, but stop kidding yourself into thinking you're burning 1100 calories riding at 12.6mph for an hour.


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## lulubel (18 Sep 2011)

amaferanga said:


> A power meter. The only unknown is your efficiency, but this doesn't vary much between individuals and for a given person it changes little if at all with changes in fitness. Certainly should be possible to compute calories burnt to within 10% for anyone.



A power meter only records chemical energy that has been converted into kinetic (movement) energy required to move the bike. It doesn't record chemical energy that has been converted into electrical energy (within the body's nerves) or heat energy. Just 2 examples. In most kinds of energy conversion, heat is a massive "waste" of energy. Our bodies generate a lot of heat - that's why we sweat.

Your posts are as evangelistic about power meters as other people's are about heart rate monitors for calorie calculation, but you're just oversimplifying a massively complex process.


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## amaferanga (18 Sep 2011)

lulubel said:


> A power meter only records chemical energy that has been converted into kinetic (movement) energy required to move the bike. It doesn't record chemical energy that has been converted into electrical energy (within the body's nerves) or heat energy. Just 2 examples. In most kinds of energy conversion, heat is a massive "waste" of energy. Our bodies generate a lot of heat - that's why we sweat.
> 
> Your posts are as evangelistic about power meters as other people's are about heart rate monitors for calorie calculation, but you're just oversimplifying a massively complex process.



I give up. If you still believe that you can calculate calories burnt from HR then I suspect that your mind is made up and closed and that you won't even consider that the _science _behind that is flawed.


A power meter will be consistent for everyone with only one assumption. HR based estimates could be way out or they could be close, but you'll never really know for sure.


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## lulubel (18 Sep 2011)

amaferanga said:


> I give up. If you still believe that you can calculate calories burnt from HR then I suspect that your mind is made up and closed and that you won't even consider that the _science _behind that is flawed.



I notice that I'm losing weight at the rate I expect with the calorie deficit I've created using the figures from my current HRM. I've used other HRMs in the past, and they haven't given me the same figures, or the same results. I also don't claim that any HRM will give accurate figures for any individual. I do claim it's better than using distance and time to guess calories, which can give wildly inaccurate figures.



amaferanga said:


> A power meter will be consistent for everyone with only one assumption.



Consistent, yes. But consistently right is very different from consistently wrong.

Also, as you can see from my post above, a power meter disregards a significant amount of chemical energy use. Basing calorie input on figures from a power meter will result in the body receiving insufficient energy input and making adaptations to improve efficiency in energy use. This is an excellent result if your goal is increased performance, but a very bad result if your goal is weight loss. If you are trying to lose weight, you want your body to use energy as inefficiently as possible.



amaferanga said:


> HR based estimates could be way out or they could be close, but you'll never really know for sure.



I know for sure that I'm logging the calories my HRM gives me and I'm losing weight at the rate I expect.


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## VamP (19 Sep 2011)

lulubel said:


> Your posts are as evangelistic about power meters as other people's are about heart rate monitors for calorie calculation, but you're just oversimplifying a massively complex process.




No. Unlike you amaferanga knows what he's talking about.

Still, carry on as you are, you are only kidding yourself, and not causing any harm


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## VamP (19 Sep 2011)

lulubel said:


> I know for sure that I'm logging the calories my HRM gives me and I'm losing weight at the rate I expect.



You're adding up two wrongs and coincidentally getting a right. Good for you. Now stop spreading the nonsense.


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## Rob3rt (19 Sep 2011)

I dont know how these Garmin algorithm's work, however I would expect them to only use HR as some sort of scaling factor, as given a proper minimum HR and a tested max HR it is sort of like an percieved exertion, the device percieves you to be working to a certain intensity and thus can adjust its output (of course its an indirect measure thus anything infered from this is subject to error). I would be doubtful of such a device only taking into account HR.

A power meter will give the best measure no doubt, however it still will not be truly accurate. But really, who needs super accuracy?


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## VamP (19 Sep 2011)

Rob3rt said:


> A power meter will give the best measure no doubt, however it still will not be truly accurate. But really, who needs super accuracy?




Totally agree. Most people will be better off by assuming 500 calories per hour of fairly intense cycling, than almost anything else. Any efficiency variations from that will be less than 10%. Well below what is actually controlable within a daily diet. And way better than letting a cock-a-hoop website con you into believing you can burn more than twice what you actually are burning.

Not a big problem if you only cycle a couple of hours a day, but if you're riding 5+ hours regularly you'll get into some serious overeating


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## lulubel (19 Sep 2011)

VamP said:


> No. Unlike you amaferanga knows what he's talking about.
> 
> Still, carry on as you are, you are only kidding yourself, and not causing any harm



I don't doubt that amerferanga knows what he's talking about, but what he's talking about is only one very simple part of the science. Unfortunately, calculating required calorie consumption is far more complex than:

BMR + day to day activity + what my power meter says = how much I need to eat

The human body isn't a computer, and anyone who believes you can calculate its needs with a few basic equations is living in fantasy land.


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## lulubel (19 Sep 2011)

VamP said:


> Totally agree. Most people will be better off by assuming 500 calories per hour of fairly intense cycling, than almost anything else. Any efficiency variations from that will be less than 10%.



You must have been undereating for a long time if you get by on 500 calories per hour for intense cycling. If I ate that little, the weight would be dropping off me - until my body went into starvation mode, of course, and I stopped losing weight altogether.


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## VamP (19 Sep 2011)

lulubel said:


> The human body isn't a computer, and anyone who believes you can calculate its needs with a few basic equations is living in fantasy land.




Well, those of us who don't have your magical crystal ball make do with science and a few basic equations. 

Obviously if science does not fit your belief system, then you need to find something else to believe in.


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## jowwy (19 Sep 2011)

I dont know why some people are getting a tad over heated in this debate as were only voicing our opinions - based on our own personal experience......

and when it comes down to assumptions - then no-one can be write or wrong.

but hey its all good fun and a good debate topic, but lets not fight to the death here and just agree to disagree.

i'm training by bike ony, i sit at my desk all day working on spreadsheets and visio charts, i eat fish, salads, pasta's rices, i use a HR monitor to work out my calories burnt during excercise and i'm losing weight in the way i want too. So am i right or wrong in what i'm doing - who cares, its working for me!!!!


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## VamP (19 Sep 2011)

It's not really a matter of opinion though jowwy. Like you can't really reasonably be of the opinion that the Earth is flat anymore.

Here, read this, and if you still not sure about things then come back.


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## Rob3rt (19 Sep 2011)

jowwy said:


> I dont know why some people are getting a tad over heated in this debate as were only voicing our opinions - based on our own personal experience......
> 
> and when it comes down to assumptions - then no-one can be write or wrong.
> 
> ...



The problem with bad assumptions is whilst you may be loosing at present (most people will loose weight upon taking up exercise and eating a bit better) when you eventually platou, and making the right adjustments to your diet and or exercise becomes a finer art, then you may begin to struggle to maintain your progress because of the poor assumptions skewing your calculations etc.


I dont bother calorie counting.


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## jowwy (19 Sep 2011)

Like i said VamP - its working for me and thats all that matters.


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