Understanding Your Blood Pressure

Blood pressure gauge with heart
Peter Dazeley/Getty Images

Obesity is a cause of high blood pressure, and both are risk factors for cardiovascular disease, so it is important to know and understand your blood pressure numbers. Knowing your numbers is the first step toward taking control of your health.

Normal Blood Pressure

Your blood pressure will usually be measured at every healthcare visit of any kind. This is because blood pressure is a vital sign—indicating that keeping it within a normal range is vital to health.

The top number of your blood pressure reading is known as the systolic blood pressure, and it is a measure of the pressure felt in millimeters of mercury (mm Hg) throughout the arteries when the heart pumps, or contracts.

The bottom number of the blood pressure reading is known as the diastolic blood pressure, and it is a measure of the pressure that remains when the heart relaxes during each cardiac cycle (the cycle from one heart beat to the next).

Normal blood pressure is considered to be less than 120/80. This means that the systolic blood pressure (top number) should be less than 120, and the diastolic blood pressure (bottom number) should be less than 80.

High Blood Pressure

The medical term for high blood pressure is hypertension, and it is known as the “silent killer” because it can be present for years without any symptoms and can cause heart disease (including heart attacks and heart failure), stroke, kidney failure, damage to blood vessels throughout the body, and many other ailments.

A blood pressure greater than 120/80 (either greater than 120 on top or greater than 80 on the bottom, or both) is technically high, but there are different levels of high blood pressure. Once the blood pressure reaches 140/90, most experts agree that this must be treated with medication in addition to dietary and lifestyle changes.

Risk Factors for High Blood Pressure

Certain conditions and risk factors are known to cause or exacerbate high blood pressure. These include obesity, heaving drinking and alcoholism, thyroid disease (particularly hyperthyroidism), smoking and physical inactivity, among others.

Having a family history of high blood pressure can make it more likely that you will develop high blood pressure yourself. Also, age is a risk factor, as many of us will see a rise in our blood pressures as we age.

Knowing and understanding your blood pressure numbers, which includes having your blood pressure checked on a regular basis, is an important first step to making sure you are getting this serious cardiac risk factor under control.


American Heart Association. Understanding blood pressure readings. Accessible online at http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/AboutHighBloodPressure/Understanding-Blood-Pressure-Readings_UCM_301764_Article.jsp#.VrUcXFnNuh4

Wilson PWF, D’Agostino RB, Sullivan L, et al. Overweight and obesity as determinants of cardiovascular risk: the Framingham Experience. Arch Intern Med 2002;162:1867-1872.

Chandra A, Neeland IJ, Berry JD, et al. The relationship of body mass and fat distribution with incident hypertension: observations from the Dallas Heart Study. J Am Coll Cardiol 2014;64:997-1002.

DeMarco VG, Aroor AR, Sowers JR. The pathophysiology of hypertension in patients with obesity. Nature Reviews Endocrinology 2014;10:364-376.

Yusuf S, Hawken S, Ounpuu S, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet 2004;364:937-52.

Continue Reading