Your blood pressure can change on a regular basis, depending on what you are doing, your diet, temperature, overall health, level of stress and the medications you may be taking. Hypertension (high blood pressure) is a common problem these days, though hypotension (low blood pressure) can sometimes cause problems too. So just what is considered "normal" in terms of blood pressure?
Blood pressure is the measure of force on the body's arterial walls as the heart pushes blood through the body. The amount of blood being pumped, in addition to how large and flexible your arteries are, determines your blood pressure. Two measurements are responsible for determining your blood pressure: systolic pressure and diastolic pressure.
Systolic pressure is the measure of pressure in your arteries when your heart contracts, and diastolic pressure is the pressure measured when the heart is at rest. The accepted measurement of "normal" blood pressure is considered a systolic measurement just below 120, and a diastolic measurement just under 80 (written as 120/80). Anyone with a measurement higher than that, but below 140/90, has pre-hypertension or "high-normal," and someone whose blood pressure is higher than 140/90 has hypertension. A measurement higher than 180/110 indicates a hypertensive crisis, and emergency care should be sought.
Though a person with blood pressure lower than 90/60 is considered to have hypotension (low blood pressure), in general, the lower your blood pressure, the better. Low blood pressure is not considered a problem unless it is causing symptoms such as dizziness, lightheadedness or fainting, in which case a doctor should be consulted, as it may indicate dehydration or a more serious medical problem.
High blood pressure is the more common problem, as it makes the heart work harder and is damaging to the arteries, leading to a greater risk of heart disease, stroke and kidney disorders. Systolic pressure rises in many people as they age, due to the buildup of arterial plaque over time and stiffening of the arteries. About a third of American adults have high blood pressure.
One high reading in itself does not necessarily indicate that you have high blood pressure. For example, many people find that just visiting the doctor's office is stressful, which temporarily raises their blood pressure while there, and it falls back to normal levels once they leave. However, if either the systolic or diastolic reading remains high over a period of time, then treatment for high blood pressure will be necessary, which can involve changes in diet and lifestyle and/or medication.