Question

To achieve and maintain physical fitness, exercise intensity should be ________ of the maximal heart rate.

Answer 1

In order to achieve and maintain physical fitness, exercise intensity should be , anywhere between 70%-85% of the maximum heart rate of a person.

Anywhere below this, and physical exercise won't be that effective. Anything more than this and it might be dangerous for the human body.

70-85% is the optimum value

Answer 2

To achieve and maintain physical fitness, exercise intensity should be 70% to 85% of the maximal heart rate.

When we do an exercise, our heart rate increases. And when heart rate increases, the body starts to burn energy that is stored in the body in the form of fats. So if anyone wishes to burn out calories/fats, the exercise intensity should be 70% to 85% of his maximal heart rate. In this way the fats would burn and the goal of fitness is achieved.