calorie burning ?

No, if your heart rate is too high then your calorie burning actually slows down. Some people need to wear a HRM in order to get their ideal heart rate.

Calories burned does increase with intensity, but it will depend on the type of exercise. For example, lifting heavy weights in a vigorous exercise doesn't actually burn that many calories even though it's very difficult and you have to push to get through those last sets (and your heart rate would be very high). But if you were to skip rope for the same amount of time you would burn more calories. the more varied (both intensity and with different body parts) your exercises are, the more calories you burn and the better results you see.