A person is considered to have reached a good target pulse when his exercise heart rate is 60 to 80 percent of his maximum heart rate. According to WebMD, a predicted maximum heart rate is determined by subtracting the person's age from 220.
WebMD notes that exercise is most beneficial and the least risky when a person exercises within his target heart rate zone. Exceeding the target heart rate zone increases both cardiovascular and orthopedic risk without added benefit. A person with a medical condition, or who is taking medication, should consult a doctor to consider if his maximum heart rate should be adjusted.