A new study suggests that it may be best to treat patients that are considered prehypertension (which means between the range of 120 to 140) in order to bring their systolic blood pressure down to 120. The findings come from a large study conducted by the National Institutes of Health. In the past, doctors have often only treated patients whose systolic blood pressure was about 140. 140 is the number that officially declares a person having high blood pressure. The reason the systolic number is of importance is because it is a better indicator of a stroke or heart attack.