Blood pressure is the measurement of the pressure or force of blood pushing against blood vessel walls. When you have hypertension (high blood pressure), it means the pressure against the blood vessel walls in your body is consistently too high. High blood pressure is often called the “silent killer” because you may not be aware that anything is wrong, but the damage is still occurring within your body. Your blood pressure reading has two numbers. The top number is the systolic blood pressure, which measures the pressure on the blood vessel walls when your heart beats or contracts. The bottom number is the diastolic blood pressure, which measures the pressure on your blood vessels between beats when your heart is relaxing. For example, a blood pressure of 110/70 is within the normal range, but a blood pressure of 135/85 is stage 1 (mild) hypertension, and so on