# Garmin Connect vs. Strava - Calorie Count Discrepancy?



## arai_speed

For some time now I've been using my Garmin Edge 500 to review my ride data, a family member suggested I join Strava so that we could each follow each other and review our rides.

I noticed that Strava greatly reduced the calories used up during a ride from that ones posted by my GPS.

For example, a 45 mile ride this past weekend read: 3,100 calories on Garmin Connect, but only 1,958 on Strava - WTF?

I'm interested in the calorie number so I know how many calories to consume during my ride (trying some stuff out) but now I'm confused as to which system to believe.

Any thoughts?


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## Christopaul

I don't know either...I have a ride calculation showing, along with mph, distance etc. on my Garmin 500. It may show 2,000 cal expended and then when uploaded to strava, it will show 1400 for example. Why the big disparity. The elevations and distances seem reasonably accurate... the calorie tracking seem to be way off... why???


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## arai_speed

I posted my same question on Strava:

Calories Spent Discrepancy? / Questions / Discussion Area - Strava Support


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## Alex_Simmons/RST

Calorie estimates from anything other than a power meter are for light comic relief only.


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## nightfend

With a Garmin 500, you need either a HR monitor or a powermeter registering for it to get even semi-accurate calorie amounts. With just a plain 500, the calorie amounts are WAY over exaggerated.


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## arai_speed

I have a HR monitor as I got the kit (computer, hr monitor and cadance meter) so I would have thought the calories read would be a bit more accurate on the Garmin.

For what it's worth, the stationary bikes at my local gym read about 500 calories per hour while doing a good workout which is similar to what Strava calculates.


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## nightfend

If you ride at around threshold, you'll probably be in the 600 to 800 calorie range. So if you are reading a lot more than that, then something is wrong.


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## arai_speed

Thanks - looking at the details for my last ride I had an Avg HR of 89 % of Max and the calories being consumed for a 1 hour period are within the ranges you listed above.


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## Undecided

nightfend said:


> If you ride at around threshold, you'll probably be in the 600 to 800 calorie range. So if you are reading a lot more than that, then something is wrong.


That makes no sense. Without knowing the OP's power at "threshold," you can't possibly guess as to the caloric expenditure. Also, as most of us use the term, a ride of more than about an hour at a sustained intensity is necessarily below threshold, anyway. The hourly caloric expenditure range you suggest implies riding at approximately 165-225 watts (on the "for convenience only" assumption that 1 kJ out of the bike requires 1 calorie into the rider). 

As Alex already said, a power meter is at least something to work with, but anything else is just a guess. Really, not informative for purposes of figuring out "what to eat on the bike" in the least. In any event, for any even remotely normal person, any ride that requires eating on the bike almost certainly involves burning more calories than one can consume.


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## nightfend

Okay, I'm assuming the OP is an average cyclist, with average body weight. In that regard, yeah, I think he will be around the 600 to 800/hour mark if he does a hard ride. Why would you assume threshold has to mean 1 hour? You can have 20 minute thresholds and 2 hour thresholds. It is simply the fastest you can go for that duration of time.


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## Undecided

arai_speed said:


> Thanks - looking at the details for my last ride I had an Avg HR of 89 % of Max and the calories being consumed for a 1 hour period are within the ranges you listed above.


Unless that ride was less than an hour, that seems really high to me (and either way, implies you were riding pretty hard). Could your maximum heart rate actually be higher than whatever number you're using? 

Not that 600-800 calories/hour are implausible numbers for a lot of people.


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## arai_speed

Thanks for replies - I actually posted the question because a while back I bonked on this particular ride so since then I've been a bit more aware of how much I need to take in.

As such I've been trying to find a balance of eating just enough to keep going but not to the point that I feel sick (which for me is a very narrow margin). So I started looking at the calories (aka "guess") to see how much I was burning during the ride to try and gauge my intake but when I uploaded my ride to Strava I was taken aback by the difference.

So it seems like w/out a power meter I'm just fooling myself?


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## arai_speed

Undecided said:


> Unless that ride was less than an hour, that seems really high to me (and either way, implies you were riding pretty hard). Could your maximum heart rate actually be higher than whatever number you're using?
> 
> Not that 600-800 calories/hour are implausible numbers for a lot of people.


I posted above w/out seeing this. The ride in question was 4 hours long and had an elevation gain of 5,223 ft.

Avg HR: 164 bpm
Max HR: 185 bpm

If I switch the view to % of Max I get:

Avg HR: 89 % of Max
Max HR: 100 % of Max


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## nightfend

Well, taking in food during the ride is a whole other matter. You definitely won't be able to eat as much as you burn. For me, I find I can go the first 1 1/2 to 2 hours without eating anything, then after that, I usually eat about 250 calories an hour.


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## arai_speed

Totally agree - I'm not trying to replenish calorie per calorie but wanted to try see what my hourly caloric spend was and see if replenishing 1/3 of what I burn works.

But it sounds like I should just listen to my body for that rather then look down the computer?


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## Undecided

nightfend said:


> Okay, I'm assuming the OP is an average cyclist, with average body weight. In that regard, yeah, I think he will be around the 600 to 800/hour mark if he does a hard ride. Why would you assume threshold has to mean 1 hour? You can have 20 minute thresholds and 2 hour thresholds. It is simply the fastest you can go for that duration of time.


I "assume" that in the context of a cycling coaching forum "threshold" (with no modifier) means "functional threshold power" or "something like CP60" or something else that's approximately a maximal effort of about an hour, because that's how it's used when bike racers and coaches talk (perhaps imprecisely) about training. While you're absolutely right that the word itself, in plain English, doesn't need to imply any period of time, in this usage, it does. Absent that assumption, though, your use of the term makes even less sense, doesn't it? If you don't think it suggests some particular meaning on its own, what did you intend to communicate in using it? 

TrainingPeaks | What is Threshold Power?

How to Increase Your Threshold Power

Joe Friel's Blog: Functional Threshold


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## Undecided

arai_speed said:


> I posted above w/out seeing this. The ride in question was 4 hours long and had an elevation gain of 5,223 ft.
> 
> Avg HR: 164 bpm
> Max HR: 185 bpm
> 
> If I switch the view to % of Max I get:
> 
> Avg HR: 89 % of Max
> Max HR: 100 % of Max


How did you determine the "max" though? Four hours at 89% of max HR sounds wrong.


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## arai_speed

*Umm....*

Does this mean posted this topic in the wrong forum??? I'm a noob and I'm only trying to learn 

Undecided, I'm only posting the data the GPS captures.


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## Undecided

Maybe the Racing/Training forum gets more discussion like this.

Not that it really matters for your original question about calories, but I think very few people could average 89% of their maximum heart rate for four hours. That's why I asked how you determined your maximum heart rate. You must have put that 185 bpm maximum into the computer at some point, whether directly or not. Maybe it's a default based on something related to your age. Do you happen to be 35?


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## arai_speed

Ha! As a matter of fact I am 35, what does that mean for my Max HR?


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## Undecided

arai_speed said:


> Ha! As a matter of fact I am 35, what does that mean for my Max HR?


It means you have no idea what it is, because you're using a default generated by the arbitrary "formula" Max HR=220-Age. There has been much discussion on the forums about how worthless it is.


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## arai_speed

The reading I provided of Max HR was for one particular ride, if I look at Max HR for other rides it differs. 

For what its worth, I've actually looked at the Max HR for all my rides, took the average and noticed the number was very close to what the "formula" renders.

Regardless I understand that short of a VO2 stress test these are all just estimates with some deviations.


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## arai_speed

Here is a great article which provides a breakdown of how Garmin determines calories used:

DC Rainmaker: How calorie measurement works on Garmin fitness devices

The Edge 500 (which is what I have) uses the First Leaf Method which provides accuracy between 7-10% and this is the best part "over time it has a weighted algorithm to note changes in your fitness level and adjust calorie burn accordingly" which I found to be true by riding the sam strech of road over and over during the last few months and noticed that with each ride my calories burned were less and less.


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## Undecided

arai_speed said:


> The reading I provided of Max HR was for one particular ride, if I look at Max HR for other rides it differs.
> 
> For what its worth, I've actually looked at the Max HR for all my rides, took the average and noticed the number was very close to what the "formula" renders.
> 
> Regardless I understand that short of a VO2 stress test these are all just estimates with some deviations.


So when you say that a ride was at an average HR that was X% of "Max HR," you mean it's just comparing the average from that ride to the highest rate during that particlar ride? What does that tell you? 

Your "maximum heart rate" must be at least the highest rate in any of those rides.


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## Christopaul

Strava makes its estimates based on "power". However, since I don't use a power meter, power is derived from the heart monitor. Has anyone gotten tested for their maximum threshold or use a power meter and use both the Garmin 500 and Strava? The burning question, is which estimate is more credible? (Stava's or the Garmin 500's).


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## Undecided

Christopaul said:


> Strava makes its estimates based on "power". However, since I don't use a power meter, power is derived from the heart monitor. Has anyone gotten tested for their maximum threshold or use a power meter and use both the Garmin 500 and Strava? The burning question, is which estimate is more credible? (Stava's or the Garmin 500's).


I think Strava's estimated power (and thus its estimated calories) are based not on heart rate, but on the weight you enter for you and your equipment, combined with the characteristics of the ride (i.e., the distance, speed and elevation change).

I usually ride with a power meter. My Garmin Edge 500's "calories" estimate is typically much more conservative than the "kJ out = calories in" method would suggest, as is Garmin Connect. (On "endurance" or "zone 2" rides, the Garmin estimates are about 50% of what the kJ=calories method would suggest). (As an aside, the Cycleops' HRM that attempts to estimate power based on the individual user completing a test to correlate HR and power suggests that the manufacturers understand that these "one size fits all" approaches to estimating calories from HR are not very useful.)

On the few number of Strava rides I've recorded *without* a power meter that I can compare to very similar rides record *with* a power meter, the Strava numbers are roughly what I would expect.


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## Cervelo S-5

Undecided said:


> Maybe the Racing/Training forum gets more discussion like this.
> 
> Not that it really matters for your original question about calories, but I think very few people could average 89% of their maximum heart rate for four hours. That's why I asked how you determined your maximum heart rate. You must have put that 185 bpm maximum into the computer at some point, whether directly or not. Maybe it's a default based on something related to your age. Do you happen to be 35?


Interesting discussion............I also have an edge 500 and use the HR monitor and cadence sensor for feedback as I do not have a power meter. I agree with Alex as well, have a little fun with the whole calorie thing and perhaps use it as a trend at best, but I would not put alot of serious stock in it. The power meter is going to be your best bet in my opinion as it will read only what you put out and will less effected by physiological variances. When I set up my Garmin, I entered my age 45 and weight 205lbs and the unit seemed to calculate the max HR for me as I never entered one ????? Oddly enough when I did a 30 min LT self test I was at a threshold of 167 (which I still feel is a little high) it correlated well with most charts that I have seen for a max of 185 . I don't get too hung up on this as I am starting to believe that my HR is just generally lower than others out there with similar levels of fitness . Even after a hard ride (TT effort or hills with a longish sprint at the end) the highest HR I have ever seen for me is 180 and I hade nothing left :mad2:. Caloric expenditures for an 80-85% HR ride for me have been reading between 1250-1350 cal for a 2 hour ride on the trainer. Although I am not really concerned with the numbers, these seem like "reasonable" expenditures to me.

Perhaps aria_speed could alter the max HR in the unit to say 200 as an arbitrary number and see what the unit comes back with as a caloric expenditure just for comparison sake. :idea:

Cheers!


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## Christopaul

thank-you! that's exactly what I wanted to know.:thumbsup:


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## arai_speed

Undecided said:


> So when you say that a ride was at an average HR that was X% of "Max HR," you mean it's just comparing the average from that ride to the highest rate during that particlar ride? What does that tell you?
> 
> Your "maximum heart rate" must be at least the highest rate in any of those rides.


No - it's not just comparing the average from that ride to the highest rate during that particular ride - it is comparing the highest HR for that ride to the "default/worthless/formula" number determined by age, in this case 185 (or any number I choose to put in there via the settings).


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## arai_speed

Cervelo S-5 said:


> Perhaps aria_speed could alter the max HR in the unit to say 200 as an arbitrary number and see what the unit comes back with as a caloric expenditure just for comparison sake. :idea:
> 
> Cheers!


I did think about that, maybe I'll try it and see what happens


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## Alex_Simmons/RST

arai_speed said:


> The Edge 500 (which is what I have) uses the First Leaf Method which provides accuracy between 7-10% and this is the best part "over time it has a weighted algorithm to note changes in your fitness level and adjust calorie burn accordingly" which I found to be true by riding the sam strech of road over and over during the last few months and noticed that with each ride my calories burned were less and less.


And why would being fitter mean you burn fewer calories on the same ride?

example:

same rider (me) on same 11.47km uninterrupted stretch of lightly rolling road:
Ride A: average power 198W - mechanical work done: 266kJ
Ride B: average power 298W - mechanical work done: 329kJ

Different conditions, different power, different calorie demand (~25% different).

All these estimation tools are works of fiction. Even a power meter can't claim to measure energy _metabolised_ to that level of accuracy, since the power meter doesn't know your gross mechanical efficiency at any given time. It accurately measures mechanical work done, and that's by far the most accurate means of estimating calorie demand.


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## arai_speed

I'll assume your question was rethorical as you are a cycling coach and seem to have all the answers.


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## Alex_Simmons/RST

arai_speed said:


> I'll assume your question was rethorical as you are a cycling coach and seem to have all the answers.


I have some, not all. Being a coach sure doesn't mean you know it all. But as an evidence based coach I try to make it my business to know and/or learn about stuff that's real and to distinguish the important stuff from the fluff.

Nevertheless, don't believe what I say on the basis of who or what I am, but rather on the merits of the information and / or evidence provided.

IMO / IME, calorie estimators are fluff.


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## wim

Alex_Simmons/RST said:


> IMO / IME, calorie estimators are fluff.


Serious question, but from someone who doesn't even have a USD 19.95 "cyclometer" on his bike now: even if they weren't fluff, what would you use those calorie numbers for? I wished there had been power meters back in the day, but the astounding usefulness of these is obvious to me.


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## arai_speed

Alex_Simmons/RST said:


> I have some, not all. Being a coach sure doesn't mean you know it all. But as an evidence based coach I try to make it my business to know and/or learn about stuff that's real and to distinguish the important stuff from the fluff.
> 
> Nevertheless, don't believe what I say on the basis of who or what I am, but rather on the merits of the information and / or evidence provided.
> 
> IMO / IME, calorie estimators are fluff.


Thanks for the feedback Alex.


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## Alex_Simmons/RST

wim said:


> Serious question, but from someone who doesn't even have a USD 19.95 "cyclometer" on his bike now: even if they weren't fluff, what would you use those calorie numbers for? I wished there had been power meters back in the day, but the astounding usefulness of these is obvious to me.


If you mean calorie estimates, then not much other than perhaps monitoring daily calorie balance for the purposes of body weight management. Which of course is problematic if the estimates are way wrong.

If you mean training with power, well that's a whole 'nuther matter - the following link gives a summary of that - see the paragraphs under "Train with Power":

Turbo Studio

Stuff like that could fill a good book. Like this one for instance:

A Training and Racing with a Power Meter 2nd Edition - U.S. ORDERS ONLY


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## wim

Yes, I meant calorie estimates. Thought perhaps there was some use for those numbers other than just weight control. I understand the usefulness of a power meter. Thanks for the reading tips!


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## Alex_Simmons/RST

wim said:


> Yes, I meant calorie estimates. Thought perhaps there was some use for those numbers other than just weight control. I understand the usefulness of a power meter. Thanks for the reading tips!


Well if they were from measurement of power (e.g. on a gym bike), then of course tracking how many calories you can manage to hit for a given interval of time is a way of tracking fitness (since that's effectively assessing average power for the duration, energy = power x time).

e.g. 2 months ago in a 20-min max test effort you logged 240 Cal, and this month you logged 265 Cal for same duration, would mean you are fitter (average power is up 10%). _Providing of course the calorie measurement is based on power delivered at cranks and the unit is consistent in its measurement day to day._


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## wim

Thks, makes sense.


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