# Thread: computing calories burned per mile

1. ## computing calories burned per mile

I'm trying to find an online site that calculates calories burned per mile, for average mountain bike riding. Most of the sites I've tried calculate calories burned by time - so if I say a 14 mile ride takes 2 hours it says I burned twice as many calories as if I said it takes 1 hour - which is obviously wrong.

I don't have any budget for buying new gadgets like a GPS or heart rate monitor. I need a way to map my ride (I'm using mapmyride.com for this) and then calculate/estimate calories by the distance traveled and my weight.

Also, when you enter the weight should you include the weight of the bike, or do the formulas assume an "average" bike weight in addition to rider weight?

Thanks!

2. Mt bike is more or less a sporatic type excercise full of intervals, unlike road biking which is usually a constant cadence with a constant heart rate mile after mile. So, I think for mt biking calories per time would be better than calories per mile. For example, A 14 mile mt bike ride at my local trail may take me 1 hr with an average heart rate of 80% which would equate to let's say around 800 calories. However, another 14 mile trail which is much more technical or has more climbing may take me two hours with the same 80% heart rate and I would burn 1600 calories. Therefore, calories per time, not per mile would be correct.

Now if you looked at the "same" 14 mile trail and one day it took you two hours with a AHR of 65% and you did it the next day in 1 hour with a AHR of 85%, then you may be correct that you burn more calories in the one hour than the two, you won't know unless you have a way to track exertion.

So if you don't want to buy a heart rate monitor you will have to use a RPE or rate of perceived exertion. With a lower RPE burning less calories per time than the higher RPE. I have seen other websites which track calories per time based on average speed which would somewhat represent a RPE.

Sorry, I know I didn't answer your question, I just want to stress that calories per mile might not be the most accurate without measuring exerition in one way or another.

3. I just thought of an easier comparison as to why exertion level is required.
I can ride 14 mile UP the mountain in two hours at an average speed of 7 mph and average heart rate (AHR) of 80%.
I can ride 14 mile DOWN the mount in 1 hour at an average speed of 14 MPH with never spinning the pedals and my heart rate is below 60% the whole time.

Which do you think will burn more calories, 1 hr DOWN, or 2 hr UP.

4. Calories Burned is all about HR... Buy a Polar HR Monitor and be done with it... Too many variables in Mountain Biking to come up with a good middle of the road guess... Your calorie burn is forever changing as you become more fit and take less effort to do the same job causing you to burn less calories than before doing the same job... You can get a HR Monitor for around 50 or 60 bucks that will do the job... Start savin it won't take long... Or sell some extra bike parts laying around... That is what I usually do... You just can't find out accurately without it... Good luck...

5. All my rides start and end at the same point (no one-way rides), so every ride up has a corresponding ride down. I assume that mountain biking calorie calculations take this into account.

6. With walking/running, the same number of calories are burned per mile no matter your speed. It takes a certain amount of effort to move your body a mile. If you walk at a 3 mph rate, or jog at a 5 mph rate, or run at a 10 mph rate, you still burn the same amount of calories per mile. What changes is how many calories you burn per minute - obviously the faster you go the more distance you cover per minute and the more calories you burn per minute. As a person becomes fitter they can do the work in a shorter amount of time, so their calories burned per hour goes up, but they still burn the same amount of calories per mile.

This is why I'm not convinced that a HR monitor is all that helpful, and as I noted in my first post I don't have any funds to buy any devices.

7. I would suspect a lot of website calculating calories per mile or hour may be a little skewed towards the non-regular rider who goes around the block every once in a while, as opposed to someone who gets out and shreds it a little. For instance, weight watchers considers bike 'racing' as over 12mph, which for a road bike is kinda slow for a race.

I'd say figure your own burn per RPE (as mentioned above) and do your own estimate. I burn between 500 and 1000 per hour, depending on how hard I pushed it. for a 9rpe,I'd be close to the 1000 calories, an easy spin, 500. I bet your estimates would be just as good, if not better than the website, either by mile or time.

8. Here's the problem with all these suggestions to use time - what about breaks, and what about changing fitness, and what about the weather? If I'm climbing a hill on a hot day and I get over-heated and stop for 10 minutes, and later I take a water/snack break, etc. at the end of the ride I have an undetermined amount of "break" time. However I still have a specific distance I traveled.

It takes a certain amount of energy to move a given weight (me and my bike) a given distance. That doesn't change depending on how long it took! I know this may seem counter-intuitive to some of you (and it's certainly not included in all these calorie counters that work off of time instead of distance) but doing something faster doesn't burn fewer calories because you still have to move that same weight that same distance. If I can do a loop in 2 hours, and someone else (same weight of rider+bike) can do it in 1 hour, we both burn the SAME total calories. As you become fitter you can burn more calories per hour by going faster, but you don't burn more calories per mile. As you lose weight you burn FEWER calories per mile because you are moving less mass. This is why calculating by time gives totally screwed up results, calculating by time results in a false conclusion that the longer it takes to go a set distance the more calories it took.

If you know the weight, and you know the distance, and you have a formula that does a good job of estimating how much "work" it takes to ride a mountain bike (as opposed to a street bike on paved roads, as opposed to running) then it should do a fairly good job estimating calories burned by weight and distance, and ignore time. That's what I'm trying to find.

9. Originally Posted by jcdill
Here's the problem with all these suggestions to use time - what about breaks, and what about changing fitness, and what about the weather? If I'm climbing a hill on a hot day and I get over-heated and stop for 10 minutes, and later I take a water/snack break, etc. at the end of the ride I have an undetermined amount of "break" time. However I still have a specific distance I traveled.

It takes a certain amount of energy to move a given weight (me and my bike) a given distance. That doesn't change depending on how long it took! I know this may seem counter-intuitive to some of you (and it's certainly not included in all these calorie counters that work off of time instead of distance) but doing something faster doesn't burn fewer calories because you still have to move that same weight that same distance. If I can do a loop in 2 hours, and someone else (same weight of rider+bike) can do it in 1 hour, we both burn the SAME total calories. As you become fitter you can burn more calories per hour by going faster, but you don't burn more calories per mile. As you lose weight you burn FEWER calories per mile because you are moving less mass. This is why calculating by time gives totally screwed up results, calculating by time results in a false conclusion that the longer it takes to go a set distance the more calories it took.

If you know the weight, and you know the distance, and you have a formula that does a good job of estimating how much "work" it takes to ride a mountain bike (as opposed to a street bike on paved roads, as opposed to running) then it should do a fairly good job estimating calories burned by weight and distance, and ignore time. That's what I'm trying to find.
1) just don't include the 'break time' in total time, problem solved.
2) your method doesn't accoutn for incline which when moving a weight makes a considerable difference, I can cover 20 miles flat in about the same time as 10 miles on a 6%grade...and I'll add, I worked a lot harder for that 10 miles...

If you are really chasing exact burn counts, you should probably really made the jump to an hR monitor. We're just trying to help.

10. jc - your not getting it... you have to do some research on hr and calorie burning in reference to changing fitness levels,weights, and terrain changes, etc, etc... I am a certified personal trainer and the points you are making are just not the case... For instance... One of your statements is as you become fitter your calories per hour goes up... That is incorrect... Just because your moving faster does not mean your heart is because it has adapted to what you are putting it through... You do more work at less of an elevated heart rate...
You are correct by saying they can do more work in a shorter time... But that does not mean the calories burned went up if they are more fit because your heartrate will stay lower and do the extra work without the extra effort... Some of this is hard to explain via forum and seems to get jumbled up while I'm trying to word it correctly... Good luck with it... HR Monitor is the ONLY way to go to get it right...

11. Basically in a nutshell your formula doesn't take into account changing fitness levels...

12. Try this, it has distance mapping and a calorie counter, just zoom in on your home town and hit the start mapping button...

http://www.gmap-pedometer.com/

13. I found this site extremely helpful in my weight loss journey. I never factored how many calories I was burning per ride. I just figured out BMR/RMR and activity level went from there. It gives round about numbers and I just played around with the numbers. The tutorials are real good

http://www.caloriesperhour.com/

14. Why question, get the data.

Love my Polar HR.

Affordable at HeartRateMonitorsUSA.com

Been very pleased with their selection, price, and service. Many a friend share the same....

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15. Originally Posted by 1FNG
jc - your not getting it... you have to do some research on hr and calorie burning in reference to changing fitness levels,weights, and terrain changes, etc, etc... I am a certified personal trainer and the points you are making are just not the case... For instance... One of your statements is as you become fitter your calories per hour goes up... That is incorrect... Just because your moving faster does not mean your heart is because it has adapted to what you are putting it through... You do more work at less of an elevated heart rate...
You are correct by saying they can do more work in a shorter time... But that does not mean the calories burned went up if they are more fit because your heartrate will stay lower and do the extra work without the extra effort... Some of this is hard to explain via forum and seems to get jumbled up while I'm trying to word it correctly... Good luck with it... HR Monitor is the ONLY way to go to get it right...
Hi 1FNG, you seem to have some knowledge on this subject so I hope you can find the time to answer this question that I have been pondering, it's also somewhat related to the OP.

I do RPM (spin) classes at the local gym and wear my HRM to help keep me motivated to push harder. The class advertises that people can burn up to 600cal per 45min class. My HRM reports that I usually burn more than that, about 700cal on average.

Now my question is........as you get stronger and fitter, wouldn't you burn more cal per heart beat due to being able to produce more watts at a lower heart beat? Thus making the HRM Cal burn per beat calculation less accurate?

Or..........When you get stronger and fitter does the body become more efficient at using available energy (cal) so the HRM calculation remains accurate?

Thanks for any help in clearing up this point

16. ## Basic physics.

Basic Physics: It takes a certain amount of energy (e.g. fuel for vehicles, calories for animals) to move a given mass a given distance, and the amount of time it takes to accomplish this is irrelevant. See this page with work/energy formulas.

Originally Posted by 1FNG
For instance... One of your statements is as you become fitter your calories per hour goes up... That is incorrect...
1FNG, You are mis-stating what I said. What I said was that as you become fitter, you can go faster, and as you go faster you cover a given distance in less time, THEREFORE as you go faster your calories per hour goes up. If you are fitter but don't go faster, you don't burn any more calories per hour (over the same course - obviously you would burn more calories if your course becomes more difficult as you become fitter). The calories you need to perform given work (e.g. "bike 10 miles") may actually go down as you become more efficient in the task (less wasted energy) but this will normally be a relatively small change and not significantly affect the overall calculations.

Formulas based on time can't be anything other than widely inaccurate - as you become fitter and then go faster you perform the same amount of work in a smaller unit of time (fewer minutes or hours), and thus burn more calories per unit of time (per minute or per hour). As noted at the beginning, the amount of energy needed to move a given mass a given distance doesn't change just because it takes 30 minutes more, or less, to accomplish the work.

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