" Great job,” your nurse says. “120/80!” If you’re not quite sure what those numbers mean, you’re not alone. But knowing your numbers and what they mean can go a long way in preventing heart disease and a host of other illnesses. The team at SIU Medicine is here to help you learn about your risk factors for heart disease, what is considered a normal blood pressure and what is a red flag. Experts agree: Understanding your results is key to controlling high blood pressure. The top number This number, also called systolic blood pressure, is the first of the two numbers in a blood pressure reading