In recent years, people have been encouraged to estimate their body mass indexes (BMI) to help assess cardiac risk. BMI is meant to be an estimate of whether you are of normal weight (for your height), underweight, overweight or obese. However, recent evidence suggests that, at least for people in the "overweight" category, the overall level of cardiac fitness and the amount of abdominal fat may be more important than BMI. Read more about it here.