Mountain Biking = Cardio?

[Davey]

When doing cardio on the eleptical machines I go by calories burned. I run until I burn 500 calories, which usually takes me a bit under 40 minutes. Now that the weather is nice I have been mountain biking. I've done two 20 mile trips and according to my cheap bell odometer my max speed was 18.4 mph and average was 12.5mph.

When I am done burning 500 calories on the eleptical I am totally soaked and I feel like I had a great workout. When I am done with the 20 mile bike trip I am hardly soaked. So I am basing the effectiveness of my cardio workout based on how much sweat I produced. So my question is: is bike riding a good form of cardio or no?

[heathj]

i think it is a great form of cardio. do you ride on a singletrack w/ roots, jumps, etc. or on gravel? i would not base a good workout on sweat, but rather, what is your average heart rate? 20 miles on a mountain bike is a good distance!