Hey guys, new to fitness...calories burned lifting?

Heya,

I've always come at losing weight in a half-*kitten* manner, and I'm ready to do it appropriately. I picked up a heart rate monitor, and I just finished my first day at the gym.

I'm following a very basic routine that only uses machines.

Once I arrived at the gym, popped on my HRM, set my weight to 220, started with a brisk paced walk to warm up - and then I worked every muscle group for 3 sets of 15 on various machines.

In total, with the person at the front desk pointing me around showing me which machines were which, it took me about 74 minutes to start and finish my workout.

By the end my HRM said I had burned 782 calories in that time frame (it's a Polaris with a chest strap). I calculated my BMR on here and deducted roughly 100 calories, figuring that's what I would burn if I was sitting on the couch.

However, I find it hard to believe that weight lifting and a little bit of walking really burned 680 calories in ~an hour. That's what I used to burn running at a pretty good clip for half an hour to 45 minutes...

Is my HRM way over shooting my caloric burn, do you think? Or is it more related to my never having lifted weights before and my body not being used to the movements?

I think I had hell of a work out, I can barely lift my arms (legs I kept way under estimating the weight for though, I'll have to up that a hefty notch next time).

Also, eating back all these calories would make me feel gluttonous...