What to do if heart rate v sweat which is a better measurement for calorie burn up?

Heart rate: Consider this: you exercise at 85% of your maximum predicted HR for 30 minutes and burn up X calories (depends on your age, weight, sex). Versus-you sit at your desk for 30 minutes in 85° temperature pouring off sweat, burning 0 (or very few) calories. Heart rate wins because it is more directly proportional to your muscular work. (at least, that's my opinion). But it's a GOOD question!!