I wore my Garmin heart rate monitor cycling yesterday (for the first time) just to see what sort of heart rates I was getting on a long ride.

Everything on it was accurate, including the distance I had gone, (matched my bike computer to within 1km) but it said I had burnt 3800 calories! This is for a 3.5 hour, very hilly ride.

Is it really possible to burn so many calories or should I not be relying on this function?

Thanks everyone...

Yes, it's possible, but you'd want to be 120kg and riding at about 80% VO2max!

I find that the Garmin 305 overstates the calories burned by quite a bit when I'm on the bike. My old polar and also an Oregon Scientific HRM that I use are more accurate and so I know about what I burn from them.

FWIW, I'm 33, 68kg, ride a really crappy old road bike and burn about 720 calories per hour at an average heart rate of 140 (VO2max = 194).

J.

Great! Thanks for that! My stats are pretty much the same as yours so 720 calories gives me a better indication...

I'll just pay attention to the heart rates for future cycling expeditions...

Did you have it set for "Biking"?
Have you uploded to TC or Sporttracks? What did they show.

Um, yeah, I actually had it set for running....I'm just using Garmin performance centre at the moment and trail runner because I have a mac and can't seem to get sporttracks working at the moment...

This might sound like a stupid question but can it differentiate between running and cycling?