How many calories am I really burning?

[mrmacmusic]

Just curious... my commute is 14.25 miles (each way), and I'm averaging about 53/54 mins these days which works out just shy of 16mph. According to the Runkeeper App that I use to track my miles, this burns approx. 600 calories.

I did a long (for me) 43 mile run a few weekends ago, and again the average speed was 16mph with a suggest calorie burn of over 1700.

The app database knows my weight (168lbs), but surely the amount of calories burned will depend on how hard I'm actually working (e.g. spinning or grinding), or am I not understanding things correctly?

I don't want to know precisely, just whether or not the number of calories that Runkeeper suggest I'm burning is a reliable guide at all.

 

[VamP]

If you assume on average 500 calories per hour you will not be a million miles off. Most apps and computers overestimate calorific burn, and are best not relied on. Your weight only has a tangential impact on the burn.

 

[marzjennings]

I usually average about 1000 calories an hour, but I'm about 230lbs and attempt an average speed of 20mph.

The estimate of 1700calories at 16mph for 43 miles sound about right.

 

[VamP]

I usually average about 1000 calories an hour, but I'm about 230lbs and attempt an average speed of 20mph.

The estimate of 1700calories at 16mph for 43 miles sound about right.

Sorry dude, but you really don't. Unless you only ever ride uphill (and off road)

 

[amaferanga]

I usually average about 1000 calories an hour, but I'm about 230lbs and attempt an average speed of 20mph.

Really? How do you know that? What's your power output?

Flat where you ride I guess, but then you do say you only attempt at average speed of 20mph ....

 

[mancaus]

If you want another data point, try http://bikecalculator.com/index.html. I use it for all sorts of fantasy, "what ifs".

 

[marzjennings]

Sorry dude, but you really don't. Unless you only ever ride uphill (and off road)

Sorry dude, but yes I do and that's being conservative on the average.

Off road the average goes up to around 1100.

Calories burned based on time, heart rate, weight and effort.

 

[marzjennings]

Really? How do you know that? What's your power output?

Flat where you ride I guess, but then you do say you only attempt at average speed of 20mph ....

Last time I did a power test I averaged 265 for the hour, though I feel stronger these days and I'm thinking of fitting a power meter.

Mostly flat, but with a lot of junctions. My moving average is usually around 21 on the road, but with all the stops usually my overall average for a ride is about 19, hence the attempt at 20 average.

 

[VamP]

Sorry dude, but yes I do and that's being conservative on the average.

Off road the average goes up to around 1100.

Calories burned based on time, heart rate, weight and effort.

The guys riding to Boulogne right now are averaging a little under a 1000 calories per hour. Unless you are using a power meter, you're just relying on one of the overestimating sites/computers. Which is massaging your ego. And by the sounds of it your backside....

If you are using a power meter, and are really burning an average of 1000 calories you have my hearfelt apology... and why the hell aren't you in the peloton right now?

Edited: Apparently you re not using a power meter. In which case the mind boggles as to how you think you are measuring effort??? Heart rate and weight are tangential to say the least. Time is important yes, but we already said a number of calories for a given time and distance. One hour at average of 20 mph I burn less than 600 calories. So will pretty much everyone else, unless it is very hilly.

 

[MattHB]

as said, without a power meter its impossible to be sure.

I find strava the most believable.. but to show you the difference: The century that I rode this weekend, which took 7hrs and 20mins with an ave of 14mph (4200ft), strava suggested I burned 3800 and cyclemeter said I burned over 7000!! That was with a HR monitor and the algorithm 'accounting' for gradient.

500 per hour is what I use when trying to work out my calorie deficits.. anything else is just way out and I plateau or gain weight. So it must be bang on.. for me at least.

be as conservative as you can, anything else is just fantasy

 

[defy-one]

My Garmin is about right then. Did 32.5 miles in 2 hours 10 mins and it said i burned just over 1000 calories

 

[smutchin]

I use myfitnesspal to record my food and exercise. When logging cycling workouts, I round down to the bracket below my actual speed (eg if I ride at 16mph, I log it in the 12-14mph bracket). Given that my weight loss (or gain) seems to follow a reasonably predictable pattern based on the myfitnesspal estimates, this seems a fairly reliable method.

So, for 40 minutes at "14-16mph" this morning (actually 29.3km/h = 18.2mph), myfitnesspal tells me I burned 446 calories. Sounds like a reasonable guess.

My Garmin, used with an HRM, gives me 396 calories for the same ride.

d.

 

[MrJamie]

Theres so much to take into account that its hard to measure, even with a power meter one persons muscle efficiency varies significantly from another.

For cycling..
Strava has me at upto 700 calories per hour.
Endomondo has me at about 1200 calories per hour.
Sportypal has me at about 1200 calories per hour.

By comparison for running..
Strava puts me at 1460 per hour.
Endomondo puts me at 1200 per hour
Sportypal puts me at 1250 per hour

While these estimates might be a bit high, Livestrong says a 10k run typically burns 700 calories, so I dont find it that hard to believe that carrying maybe 50kg on top of the average runner requires a huge amount more effort and at 19 stone (6'2) i can still run 10k in under an hour.

Also, im sure 15mph on a full suspension Sports Direct Dunlop bike for example is worlds apart from 15mph on an aggressive geometry racing bike and a lot of these sites dont even ask for this info.

 

[VamP]

Theres so much to take into account that its hard to measure, even with a power meter one persons muscle efficiency varies significantly from another.

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.

 

[mrmacmusic]

Wow... I seem to have opened a can of worms! Thanks for the input though... it's safe to assume that Runkeeper's calorie consumption should be taken with a pinch of salt then , and is definitely on the high side.

Given that I used to weigh 252lbs and have maintained my new weight of 168lbs for 8 months now (at the request of my wife who didn't want me losing any more), I must have got the diet/exercise balance about right now. Whilst I usually cyclo-commute 5 days a week, there are odd days when I need to take the car – my food intake is pretty much the same whether I cycle or not, and there certainly isn't a 1200 calorie difference between 2 and 4 wheel days.

I still weigh myself every Saturday morning having got into that habit whilst "adjusting my lifestyle"... some weeks it'll be 11st13, others 12st 1lb – I guess my body just keeping itself right?