I have a calorie counter watch, just wondering how accurate you think they are, it measures my heart rate with a strap around my chest then tells me my heart rate and how many calories I'm burning.

Out of interests sake I actually burn more calories weight training then I do on the threadmill, this makes me wonder how accurate it is...fair enough it measures my heart rate but for all it knows I just got spooked by a ghost and my heart rate has gone up while I'm sat in a chair doing nothing!

Do they suck or is it worth keeping ?