I bought one of these GPS/HR monitor watches. It has a calorie count function based upon age, height, weight, and HR. According to it I'm burning some serious calories, even just sitting on the couch. I'm curious if any of you have this watch or a similar one, and do you think these "calories burned" numbers are accurate or at least close? I rode my mountain bike for about an hour or so with a average heart rate of 155-160 or so. It said I burned like 1,700 calories. To me, that's huge for an hour. That means if I rode for almost 5 hours I would be approaching burning 10,000 calories. To me, that's insane number and seems far fetched. I could eat McDonalds three times a day and not consume 10,000 calories.