Experts on cardiac health tell us that the best ways to keep our hearts healthy are through a balanced diet, avoiding smoking, and regular exercise. Exercise that is good for your heart should elevate your heart rate . Heart rate is a measure of how many times a person's heart beats in a minute (technically measured in beats per minute , or bpm ). But by how much, for how long, and how often should your heart rate be elevated? This has to do with how fit you are and your maximum heart rate , which is 220 bpm minus your age. For example, if you are 30 years old, your maximum heart rate would be 190 bpm (since 220 minus 30 equals 190). The American Heart Association recommends that you do exercise that increases your heart rate to between 50 and 85% of your maximum heart rate. This range is your target heart rate zone . They recommend getting at least 30 minutes of moderate to vigorous exercise most days (or a total of about 150 minutes a week).