Best way to count calories?

flyer

I have a Garmin edge 305 and the way it measures calories doesn't seem to be that accurate.

Is this the case with all of these computers or are the polar more accurate?

On average an 20 mile ride on the flat at 17.8mph tells me it burns 1177 calories!

Most people say this is out by at least 30%

When you put this data into "on line" calculators it says around 980 calories, based on weight and age.

I don't want to get too geeky about it but I would like to know what an average 20/40/60 mile burns

Thanks

Flyer

Jamey

This sort of ties in with something I was going to ask, if you don't mind me adding to the thread?

basically I was wondering whether power meters are capable of giving you an exact figure for the number of calories you're using? It would seem logical since calories are a unit of energy and a power meter measure energy expended but I know little about power meters.

If not, is there any cycling device that can give you a reliably exact figure for the number of calories you've used on a ride?

Chrissz

Very few will give a truly 'accurate' kcal count. Calorie usage during exercise depends on a number of factors including heart rate, body composition, muscle fibre type and even air temperature. Most should only realy be used as a rough guide rather than as an accurate measure of energy expenditure.

Alex_Simmons/RST

Only a power meter* will tell you how much work you've done. Even then, in order to get an accurate number of calories used in total, you need to know your own efficiency level, which can range from ~18-24%, which is the proportion of energy that ends up as mechanical work pushing the bike forward versus our total energy expenditure (most of which is dissipated as heat).

Garmins, Polars etc etc are all giving bunkum numbers.

* or a gas exchange analysis in a lab...

pinkbikini

i've always thought the obsession with counting calories burned is at least partly explained by the resultant hunger attack and calorie-loading post-ride. balancing the guilt of the post-ride binge...