how accurate?

Triangle Kebab

just wondering if anyone knows how accurate bike gps' are when it comes to calories burnt? I have a mio 300 which takes into account my weight and inclines on the route. A friend and i went out and did 17 miles yesterday (not far i know, but i am just getting over an illness and he just hasn't ridden for ages) he is using a basic cateye computer, and although our current speed, average speed and total distance were all within about 0.3 of each other the calorie count differed massively. Over the course of the 17 miles his computer was saying he had burnt around 400 calories, but my mio was saying i had burnt 1300!!!! surely that cant be right? can it??
Thanks
Si

Pross

Not accurate at all. They have nothing really on which to base their data unless you are using a power meter. You can possibly get a reasonable approximation from heart rate as long as you and the computer know your maximum but it is still an estimate. Other than that it is just a guess based on general information of how hard people work to ride at a set speed / gradient etc.

hatch87

I would say your mates one was right. My 25 mile rides come up with about 900-1000 with a HRM. But they are all guestimations

drlodge

Quick rule of thumb, about 10kcal per minute burnt, or 600kcal per hour.

marylogic

I've found that as I've been losing weight and updating my garmin that the calories burned has decreased by quite a lot for the same circuits (curses!)

I don't know if weight difference could be the reason for the discrepancy between you and your friend?

My strategy now is to avoid further weight loss by using the calories burned to inform my choices at Greggs