Working out calorific output...?

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Greenbank

Über Member
Various different devices give different figures.

My simple cycle computer (Cateye Velo 8), for example, doesn't know how much I weigh, or anything about elevation changes or the wind. It simply assumes that the faster I go the more calories I must be using, despite the fact that going fast usually means a downhill or a tailwind and going slow is either a headwind or going uphill.

Also, doing 60kph downhill is far from a rest for me as it means my legs are doing about 180rpm. ;)

For my flat commute (12km at about 26kph average) it usually gives me a reading of 240kcal.

My GPS (Garmin Forerunner 405) knows my speed, elevation, heart rate, age, weight, max HR, etc so you'd think it would have a better idea about kcal consumed. Nope, it claims, for the same commute, about 700kcal.

Based on my experience (reading books/papers, playing with GPS data, cycle computers, various websites, etc) I'd say that for an 80kg me on an average 200km Audax (i.e. 2000m climb) at a reasonable average (about 21-22kph) I use about 4500kcal. So for a similar 300km ride (with 3000m climbing) I'd use about 7000kcal.

Hillier/Faster/Heavier; add a bit. Flatter/Slower/Lighter; lose a bit.

Another way of thinking about it, I'd guess that over average terrain (10m climb per km):-

550kcal an hour if you're going hard (i.e. sub 30-minute 10 mile TT speed of 20mph+)
350kcal an hour at usual Audax pace (22kph)
200kcal an hour at pootling pace (16kph)

yello said:
Forgetaboutit, imho!

Exactly. Stick to what you can compare, such as distance, speed and time.
 

jimboalee

New Member
Location
Solihull
Calculating calories needn't be taken into seriousness until the ride is over 50km.
Unless, you start at sea level and ride to the top of a mountain.
By the time you have worked up the fitness to cover 50km in 2.5 hours, you should know what your body needs.
Going beyond 50 km requires feeding during the ride.

As a general rule, 8 kCals/min.
For climbing, half of this for every 10 meters climbed in a minute, ADDED to the grand total.
Roughly speaking, on a 10% climb, covering 10 meters horizontal distance in 6 seconds ( which is a grovelling 6 kmh ) expenditure is 12 kCals / min.
If the forward speed is double at 12 kmh ( 7.5 mph ), expenditure is 16 kCals / min.

16 kCals / min is equivalent to carrying your bike up a flight of stairs at walking pace.

Does this sound reasonable?
 

jimboalee

New Member
Location
Solihull
yello said:
...and using it to calculate my yesterday's ride gave 8099 calories, compared to the 9157 that my hrm said. Not a million miles apart I guess but I reckon these things can only ever be a ballpark... unless you have some fiendishly complex calculation, one that no doubt would include things like the "Thermo Conductivity of Lycra".

Forgetaboutit, imho!

D'wanna know about WET lycra? You might as well be NAKED :biggrin:

Thermoconductively AND visually. ;)
 

jimboalee

New Member
Location
Solihull
This morning's commute.

14 miles, 141 Degrees true.

Temp 8 Deg C. Wind 8.5 mph SSW.

55 mins, 10 s.


Garmin 605 says,,,, 902 kCals.

My calcs say,,,,,,,, 534 kCals ( entirity ), but in reality, for such a short distance, I will treat myself to 170 kCals, a tube of Maynards Wine Gums.
 

Lisa21

Mooching.............
Location
North Wales
I agree that calorie expenditure is a very grey area due to the many different things which can influence the result,although I live in hope that the above calcs are not too accurate or it sounds like you burn off the same amount of calories cycling as you do watching telly:evil:

HOWEVER.......I swear by the unoficially scientifically proven results of the FCBC (female calories burned chart) which states that:

ANY enjoyable excersise or activity burns off the equivalent of 3 standard size KitKats per hour.

Any boring, mind numbing or soul destroying activity (ie work) burns off the equivalent of 2 bars

Any mentally stimulating excersise (ie watching a DVD) burns off the calories equivalent to 3 bars and a large bag of Doritos.(cheese ones)

These figures can be doubled in value during cases of extreme PMT
(and face it-who would be brave enough to argue)

I live by these calculations and they have not done me any harm.:biggrin:
 

jimboalee

New Member
Location
Solihull
Lisa21 said:
I agree that calorie expenditure is a very grey area due to the many different things which can influence the result,although I live in hope that the above calcs are not too accurate or it sounds like you burn off the same amount of calories cycling as you do watching telly:evil:

HOWEVER.......I swear by the unoficially scientifically proven results of the FCBC (female calories burned chart) which states that:

ANY enjoyable excersise or activity burns off the equivalent of 3 standard size KitKats per hour.

Any boring, mind numbing or soul destroying activity (ie work) burns off the equivalent of 2 bars

Any mentally stimulating excersise (ie watching a DVD) burns off the calories equivalent to 3 bars and a large bag of Doritos.(cheese ones)

These figures can be doubled in value during cases of extreme PMT
(and face it-who would be brave enough to argue)

I live by these calculations and they have not done me any harm.:biggrin:

Calorie expenditure is Brilliant White in my house.

Cycling requires a balanced diet, - a box of Mr Kipling in each hand. :biggrin:
 

Lisa21

Mooching.............
Location
North Wales
jimboalee said:
Cycling requires a balanced diet, - a box of Mr Kipling in each hand. ;)


:biggrin::biggrin::biggrin: now your beginning to talk sense!!!!!!!!!!!!!!!!:biggrin::biggrin::biggrin:
 
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