Maintaining normal blood pressure should be your goal. Here's why.
At rest, a normal heart beats 60 to 100 times a minute, depending on your age and level of fitness. This means your heart beats at least 86,400 times a day or 31,536,000 times a year. That's a lot of work for a muscle the size of your fist. And just like any other muscle that is exercised, the heart will grow bigger when it is forced to strain.