How many calories am I really burning?

[lulubel]

Wow... I seem to have opened a can of worms!

This argument comes up from time to time, and it's usually fairly heated. If what you're doing is working for you, just keep doing it.

 

[MrJamie]

Actually, while those differences exist, they aren't really all that significant. Running is a different story, but for cycling weight is definitely a tangential factor in determining calorie consumption.

Id read that a bike/drivetrain can be over 90% efficient IIRC, human muscles are around 20-30% efficient at converting glycogen etc to energy and on top of the actual energy put through the pedals a lot is wasted generating heat in the body, regulating that heat, pumping blood around etc etc. Theres also post-exercise calorie burn in calorie burn and maybe boosted metabolism, which i think is why doing weights are popular for burning fat.

Id love to know what to believe though, Livestrong says that for running additional weight is linear and says over 10k (6.2 miles) a 19 stone person will burn just over 1200 calories (same as the sports apps say), skinny ethiopian runner probably wont burn much more per hour but will run twice as fast and more efficently. Surely if I go out for an hour on the bike breathing as hard, high heart rate, dripping with sweat trying as hard as I can its not impossible I could burn a similar level of calories? Ill have to have a look at what my cheapy hrm says.

 

[NotthatJasonKenny]

I'd love to think that my short 15 mile ride today burnt off the 1000 calories which cyclemeter says it did but it doesn't know how much I pedalled, uphills or downhills...well it knows the terrain from the gps but it doesn't know if I flew down or coasted...well it could work it out from the gradient and speed but...

Anyway, I usually halve it and am happy at that!

 

[MattHB]

I'd love to think that my short 15 mile ride today burnt off the 1000 calories which cyclemeter says it did but it doesn't know how much I pedalled, uphills or downhills...well it knows the terrain from the gps but it doesn't know if I flew down or coasted...well it could work it out from the gradient and speed but...

Anyway, I usually halve it and am happy at that!

Export the tcx file to strava, it's interesting to see the differences. You can do this by email, it's very easy once you set it up right

 

[Garz]

Just curious... According to the Runkeeper App that I use to track my miles, this burns approx. 600 calories.

I normally apply a 30% reduction to the digital calorie counters from devices. So probably closer to 400!

My Garmin always over-eggs the calories, as did my smartphone etc.

 

[ColinJ]

About 30-40 Cals/mile!

 

[Thomk]

About 30-40 Cals/mile!

Yep. OP just wanted an approximation and I think this is as good as anything.

 

[ColinJ]

Yep. OP just wanted an approximation and I think this is as good as anything.

My experience is of losing 1 pound per imperial century, and 1.25 pounds per double metric century (200 kms = 125 miles), thus 3,500 Cals per 100 miles, 35 Cals/mile. I've consistently done that on probably 30+ 100 mile and 200 km rides. The numbers back up what I've read on reputable websites, and have calculated using some convincing-looking online cycling calculators, for example this one.

 

[MattHB]

My experience is of losing 1 pound per imperial century, and 1.25 pounds per double metric century (200 kms = 125 miles), thus 3,500 Cals per 100 miles, 35 Cals/mile. I've consistently done that on probably 30+ 100 mile and 200 km rides. The numbers back up what I've read on reputable websites, and have calculated using some convincing-looking online cycling calculators, for example this one.

I put in everything from my big w/e ride and it came out 23 less than strava. So providing that site is good, strava is pretty bang on

 

[MrJamie]

I like that calculator and it seems to have me at about 700-800 cals per hour (15-16mph). I dont think the bar tops position quite represents sat upright on a mtb/hybrid with the aero traits of a brick wall though, since it makes rather small differences to effort required. Interestingly each 1% grade adds ~200 calories per hour too.

The other thing these estimates are poor with IME is braking, if you were to accelerate to 20mph, brake to 5, then accelerate to 20 repeatedly for an hour youd use a lot of energy, but the estimators would only see your 10 miles at <10mph average and work off that and in that sense they dont distinguish between crusing 20mph along empty country roads and frequent stopping and accelerating in urban riding.

I tend to use the calories just to quatify how much ive done in the past week or month, rather than a reliable figure that entitles me to an entire cake at the end of each ride

 

[Andrew_P]

If my garmin was right I would be 3.5 stone by now..

 

[ColinJ]

The other thing these estimates are poor with IME is braking, if you were to accelerate to 20mph, brake to 5, then accelerate to 20 repeatedly for an hour youd use a lot of energy, but the estimators would only see your 10 miles at <10mph average and work off that and in that sense they dont distinguish between crusing 20mph along empty country roads and frequent stopping and accelerating in urban riding.

Good point! Yes, they all assume constant speed. At least the one I linked to takes the weight of the bike (remember to include the weight of your clothes, drinks, tools and spares too) and wind speed into account.

My cheapo gym bike has a calories burned function which works by measuring how many revs the flywheel does during the session. All very well, except that it does not have any way of knowing how much friction I have set on the drag brake! I can wind the brake off the wheel or do it up so tight that I can't turn the pedals without standing on them and it is all the same to the computer. I ignore it apart from the timer which I use to time my intervals.

 

[mrmacmusic]

All very well, except that it does not have any way of knowing how much friction I have set on the drag brake! I can wind the brake off the wheel or do it up so tight that I can't turn the pedals without standing on them and it is all the same to the computer. I ignore it apart from the timer which I use to time my intervals.

LOL! Thanks Colin – and that 30/40 calories per mile ready-reckoner above is much appreciated

 

[amaferanga]

The other thing these estimates are poor with IME is braking, if you were to accelerate to 20mph, brake to 5, then accelerate to 20 repeatedly for an hour youd use a lot of energy, but the estimators would only see your 10 miles at <10mph average and work off that and in that sense they dont distinguish between crusing 20mph along empty country roads and frequent stopping and accelerating in urban riding.

Well firstly all they provide is a rough guide anyway.

From riding with a power meter, my experience is that stop/start riding and hilly rides actually lead to significantly lower average power than a flat (ish) road with no or minimal stops. The reason being that you just can't make up for the zero-effort parts (coasting and waiting at junctions) with the 'on' periods. My average power through the city is very low compared to what I do when I get a clear bit of road with no stops. Similarly, properly hilly rides with long descents lead to lower power than flat (ish) rides where I can keep a relatively constant (and actually quite modest compared to what I'd climb a hill at) power output.

Lower average power means lower calorie burn so I'd disagree with your statement for general riding (not so sure about you extreme example, but that's not real world riding).

 

[jowwy]

Good point! Yes, they all assume constant speed. At least the one I linked to takes the weight of the bike (remember to include the weight of your clothes, drinks, tools and spares too) and wind speed into account.

My cheapo gym bike has a calories burned function which works by measuring how many revs the flywheel does during the session. All very well, except that it does not have any way of knowing how much friction I have set on the drag brake! I can wind the brake off the wheel or do it up so tight that I can't turn the pedals without standing on them and it is all the same to the computer. I ignore it apart from the timer which I use to time my intervals.

but if you have en electronic computer on your excercise bike that adjusts the drag settings automatically which then ups the calorie expenditure accordingly its much easier