Timex HRM - Reported Calorie loss, realistic?

jimmabass

My first MFP post I bought an SX duo HRM the other day, and the chest strap just wasn't working. I took it back, and got a Timex Road Trainer HRM - a little more pricey but the chest strap works well! Seems like a decent watch all in all. My reason for getting a chest strap one is I like the no-touch instant readout of current heart rate, and I'm interested in my heart rate when drumming - I can't exactly stop and press on watch in the middle of a song

Anyways, I tried it out tonight at the gym, I did 40 minutes cardio (recumbent bike, weight loss program, more than moderate), and then 30 minutes weight training on various free weights, and machines.

I've programmed the watch with my measurements, 5'9, 208 lbs (male) and after the workout, it reported 1 HR 13 mins, AVG HR 126, PEAK HR 154, min 79. Total Calories 1057.

The heart rate reading always seems to be correct, but this cal burn, seems to me, to be extremely high, almost double? MFP reports it at 580 calories, the bike reported only 280 calories (doesn't include strength training)

Thoughts?
Thanks!