We know that people who eat poorly and don't exercise have an increased risk of heart trouble, but the opposite doesn't hold true. Just because you're at a healthy weight doesn't mean that your heart is healthy. Most notably, your heart's health is affected by genetics; a family history of health problems like heart disease, diabetes, high cholesterol or high blood pressure puts you at risk for the same conditions, no matter your weight. There are other uncontrollable risk factors as well, such as age and gender -- problems generally increase as you age, and males are more at risk for heart issues than pre-menopausal women. No matter how many miles a day you run, you need to see a doctor on a regular basis to monitor your cardiovascular health.