Although the average blood pressure of humans varies due to many factors, WebMD cites normal human blood pressure as being a systolic pressure of less than 120 and a diastolic pressure of less than 80. Blood pressure higher than 120/80 indicates a higher risk of heart disease.
Having a systolic blood pressure of 140 or higher or a diastolic pressure of 90 or higher indicates that a person has hypertension, also known as high blood pressure, reports WebMD. People who have a systolic pressure between 120 and 139 or a diastolic pressure of between 80 and 89 have prehypertension. Both hypertension and prehypertension carry an increased risk of heart disease.