How is "Calories burned" measured?

[davidtinker]

Hi Guys

 

Do any of you know how Garmin GPS cycle computers (e.g. Edge 305) calculate the calories burned on a ride? I have noticed that it is directly proportional to the weight entered on the device. Does it have anything to do with heart rate? Or is it just distance and altitude climbed?

 

I am 73kg with 9kg of bike and water and use about 1000 kcal an hour on a typical ride around the peninsular.

 

Cheers

David

 

[Capri Wheeler]

wow, then you must be working like a demon!

[Mellow]

i dont know the exact formula but it also uses the max hr you enter... ie. % of max

[Capricorn]

i'm pretty sure that medical research has indicated there is some correlation between heart rate, mass and energy usage.

 

 

 

and yes, a quick google suggests my hypothesis as correct:

 

 

 

Google Books

 

 

 

other random linkCapricorn2009-04-27 11:30:34

[GreyOwl3.0]

Guestimation...

[Mellow]

another forum where people (prob americans) discuss it. they give some formulas here...

 

http://caloriecount.about.com/anyone-understand-calculate-calories-burned-based-ft124824

 

[davidtinker]

Thanks guys. One of the referenced sites had a link to a calculator.

 

http://www.braydenwm.com/calburn.htm

 

"energy expenditure is a linear function of

heart rate over the range of approximately 90 to 150 bpm. In other

words, it is a straight line. As you would expect, everyone has their

"own" straight line..."

 

I filled in some of my figures and it comes out just under 1000 kcal. So Garmin may be using something very similar.

 

Interestingly the page discusses deriving average power from kcals burned and the calculator displays that as well.