Good blood pressure is just one factor, but it is a very important factor in maintaining future cardiovascular health. A blood pressure reading is expressed as a top number over a bottom number. The top number is the systolic pressure, the pressure inside the arteries when the heart contracts to pump blood. Diastolic pressure, the bottom number, is the pressure in the arteries between heartbeats. Good blood pressure is blood pressure that consistently falls within the normal, healthy range of 90 to 120 millimeters of mercury (mm Hg) systolic pressure and 60 to 80 mm Hg diastolic pressure.
If the systolic reading is above 120 or the diastolic reading is above 80, it is considered hypertension, which has four categories defined by the American Heart Association. Prehypertension is a systolic reading of 120 to 139 or a diastolic reading of 80 to 89. Systolic pressure of 140 to 159 or diastolic pressure of 90 to 99 is stage one hypertension. Stage two hypertension is a systolic reading of 160 or higher, or a diastolic reading of 100 or higher. Anything above 180 systolic pressure or 110 diastolic pressure is considered a hypertensive crisis, at which point the patient should receive emergency care.
High blood pressure causes several health problems that develop slowly over several years, the effects of which may not be noticed until the disease is advanced. The effects of high blood pressure are important reasons to take regular readings and make sure one is maintaining good blood pressure. Arteriosclerosis, or hardening of the arteries, and atherosclerosis, or a buildup of deposits inside the arteries, can both result from high blood pressure. High blood pressure can also directly or indirectly cause kidney damage or failure, heart damage or failure, coronary or peripheral artery disease, and brain damage.
Good blood pressure is generally considered to be 120/80 mm Hg or less, though blood pressure can also be too low. Blood pressure below 90/60 mm Hg is considered hypotension. Lower blood pressure in healthy people often indicates good cardiovascular health, but in some people, most notably the elderly, hypotension can cause a lack of blood flow to important organs. Without symptoms, low blood pressure is generally not considered dangerous, but it needs to be addressed when it causes symptoms such as dizziness, blurred vision, dehydration, fatigue, shallow rapid breaths, and nausea.
