Strava - how accurate is the calorie counter

[vickster]

Which is what I said...however major pinch of salt with guesstimate

 

[SatNavSaysStraightOn]

and then you have to work out if they are taking this as above and beyond your average 2,000 calories (female) 2,500 calories (for a man) or whether they are taking it into account - which probably explains some of the difference between garmin calories and strava calories... personally I prefer to work on the additional calories to my usually daily limit rather than taking my daily calories into account... (and if that does not have you confused, nothing will!)

 

[Rob3rt]

and then you have to work out if they are taking this as above and beyond your average 2,000 calories (female) 2,500 calories (for a man) or whether they are taking it into account - which probably explains some of the difference between garmin calories and strava calories... personally I prefer to work on the additional calories to my usually daily limit rather than taking my daily calories into account... (and if that does not have you confused, nothing will!)

eh....

 

[SatNavSaysStraightOn]

eh....

normal daily calories needed for every day life 2,000 for a woman, 2,500 for a man. Exercise uses extra calories in addition to that daily figure.

Garmin figures are always way over what strava or anything else seems to predict.

So is strava saying you have used an extra xyz calories in addition to your daily usage or does that figure include your daily calories...

so
exercise calories + 2000 (or 2500) = what you have expended over the course of that day
or
exercise calories for the hours you exercised to include standing calories for those hours as well (say 4 hours) + 20/24 of 2000 (or 2500 standing calories minus 4 hours of the day) = total energy expended over 24 hours assuming 4 hours of cycling...

just a random thought

 

[Rob3rt]

It is saying how many calories they think you have burnt during the activity you have just uploaded. That's it, nothing more, nothing less.

 

[fossyant]

It is saying how many calories they think you have burnt during the activity you have just uploaded. That's it, nothing more, nothing less.

Agree, it's just 'rubbish'. There. Keep riding folks !!

 

[SatNavSaysStraightOn]

It is saying how many calories they think you have burnt during the activity you have just uploaded. That's it, nothing more, nothing less.

so that should, in theory, take into account a proportion of your 'daily calories' then... to hold a constant body weight...

 

[Rob3rt]

so that should, in theory, take into account a proportion of your 'daily calories' then... to hold a constant body weight...

You are over complicating it.

As I said above, it is guessing how many calories burnt during that activity, nothing else. What you burnt during the rest of the day is of no consequence.

 

[Rob3rt]

I don't know what their algorithm is...

 

[JoeyB]

I'm confused too...why does it need to take into account the average calorie requirement for a man or woman? It just gives an estimate of what you've burnt...its not apportioned to anything?

 

[fossyant]

Back to the OP, none are accurate, they are just a guess.

 

[Rob3rt]

https://strava.zendesk.com/entries/20959327-Calorie-Calculation

 

[fossyant]

Cut and pasted:-

Calorie calculations are only estimates. You may notice differences between Strava's calculations and those from other tools, even given the same activity data. This is most likely due to differences in Calorie calculation algorithms, and the data factored into the calculations. We believe our estimation is as accurate as possible given the limitations in data.

Guessed !!!

 

[Rob3rt]

I have got about 18 months worth of power data, the power meter calculates energy transferred to the crank in kJ (since it knows torque and rate of rotation this can be computed), if you look up the relationship between kJ and kCal and also the accepted range of human efficiencies (25% give or take a few %), you will find that these 2 conversion factors very nearly cancel out (with some individual variance accepted).

Even though they do not exactly cancel out, assuming they do still tends to lead to a better estimate than most other methods outside of a lab, i.e. I have a pretty good idea of how many calories I am burning per mile, or per hour etc.

If I calculate total energy expended over total miles, I get the value 44.22 kJ/mile, assuming the 1:1 ratio, we come to an estimate of ~44 kCal per mile. Total energy expendature over total time riding, I get the value 770.15 kJ/hour, so an estimate of 770 kCal/hour. Of course this then suggests an average speed (all time) of 17.5 mph.

Take the 1st one, 44 kCal per mile, is close to the rule of thumb Vickster commented on. Not sure where she read that? But I have posted the above before, albeit with less data.

 

[vickster]

Can't recall to be honest! Read it somewhere as 40, I err on side of caution with 30, as although I am heavy, it's flat round here and I average 13-15mph and don't get very sweaty or out of breath!

There's stuff on the web, eg http://caloriesburnedhq.com/calories-burned-biking/