Nope
But its still useful
Mostly because it can never pick up my heart rate in the first place, so how could it know how hard I'm working. Plus, I'm assuming it uses something like an average metabolic rate, but thats not necessarily what yours is.
So I dont use it to say "i burnt 350 cal on the treadmill so i can eat a burger and be even" or to figure out how much i have lost. But I do use it as a measure of how far ive gone kinda thing. So each time on the treadmill i might focus on "burning more calories" in 45 mins, rather than trying to run a certain distance