# Actual amount of calories, I'm burning when riding bike

I've just finished my first GPS-tracked bicycle workout. I tracked my "achievements" using two different sport trackers -- Endomondo and Runastic (I'm using both in the same time purely for testing purposes).

Results reported by both sport trackers (distance, time, speeds) are nearly the same, except for number of calories, that I burned. Endomondo shows value twice as big, claiming that I burned 609 calories, while Runastic reports only 328.

I expected to find some differences, as calories burnout is a value, that can't be measured with high precise (at least in these circumstances), but having these values twice as big actually surprised me.

My workout was 45 minutes cycling, on 10,5 km distance. I'm 181 cm and my weight is 120 kg (metric).

This question is not releated to some problems in any of these sport trackers software. I'm precisely asking, which of these two presented values is (should be) more close to reality? Basing on above workout parameters, how many calories should I burn?

• at ~ 15k (9 miles) per hour, I'd be more inclined to believe runastic's figures. – JohnP Aug 18 '14 at 22:18
• I generally agree with you (and others), that Runastic's figures are more close to reality than Endomondo's ones. However, I contacted Endomondo support on this issue and the sent me to this support text, which claims, that their calories burning algorithm has an academic background (based on CPA: "The compendium of physical activity" and Keytel LR, Goedecke JH et all., "Prediction of energy expenditure from heart rate monitoring during submaximal exercise"). – trejder Aug 20 '14 at 10:49
• This is why you should follow up on things. The CPA that you reference gives 4 METS (METabolic EquivalentS) for cycling at less than 10 mph. If you plug your values into a METS to calories converter (Such as this one: ergo.human.cornell.edu/MetsCaloriesCalculator/… ), it gives a value of 270 calories for your weight/time/pace. – JohnP Aug 20 '14 at 14:32
• – arober11 Jul 21 '15 at 15:14

You do work on a bicycle to overcome wind resistance and to lift you and the bike up hills. If you do a slow flat ride, you will burn fewer calories; if you do a fast hilly ride, you will burn more. Converting the two values you give to calories per hour would be 440-810 calories.

I'm a fairly serious recreational cyclist; I ride a few thousand miles a year, and do specific training. I ride with a power meter, which directly measures how much work I do, which can be (fairly accurately) converted to calories burned. Riding all out I can put out around 800 calories/hour.

You don't mention what sort of fitness state you are in or how hard you were riding. If you are a highly-trained athlete and you've been riding for a while, 600 cal/hour might be reasonable. If you aren't very trained and you weren't riding for a while, 300 cal/hour may be a better estimate.

While cycling you need to overcome inertia, wind resistance and gravity. Inertia is related to moving weight, wind resistance to your speed and gravity come into play when you climb uphill. Various things will influence the amount of work produced on your bike, and calories burnt as a result

1. Course elevation profile
2. Wind conditions
3. The bike you ride (road, hybrid, MTB?)
4. Effort distribution (are you going at a steady pace or doing intervals?)

You can find a lot of useful information regarding power calculation for cycling in this wikipedia article on cycling performance