Originally Posted by DrIsotope

Active HR has essentially nothing to do with work done-- so average heart rate and power output (and therefore calorie burn) are not measurably related. HR is determined by a laundry list of factors. PM measured power is torque * RPM. I can make 200W with my HR in the 130s one day, and it might be in the 150s the next. The weather has a significant impact on HR. Power is power.

The OP is gonna have to do a lot of work to burn the same amount of fuel I do just toddling around. I'm 50% bigger, probably make (on average) about 50% more power, and therefore burn about 50% more calories in the same time period. I dunno if it's worth the trade.