Blood pressure is measured with an inflatable arm cuff and a pressure-measuring gauge. A blood pressure reading, given in millimeters of mercury (mm Hg), has two numbers. The first, or upper, number measures the pressure in your arteries when your heart beats (systolic pressure). The second, or lower, number measures the pressure in your arteries between beats (diastolic pressure).
The National Heart, Lung, and Blood Institute says normal blood pressure is below 120/80. Higher readings are classified as:
- Prehypertension — 120/80 to 139/89
- Stage 1 hypertension — 140/90 to 159/99
- Stage 2 hypertension — 160/100 or higher
Because blood pressure tends to fluctuate, a diagnosis of prehypertension is based on the average of two or more blood pressure readings taken on separate occasions in a consistent manner.
Oct. 10, 2012
- What are high blood pressure and prehypertension? National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/hbp/hbp/whathbp.htm. Accessed Aug. 8, 2012.
- Chobanian AV, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Hypertension. 2003;42:1206.
- Hernandez J, et al. Prehypertension: A literature-documented public health problem. Journal of the American Academy of Nurse Practitioners. 2012;24:3.
- Thompson AM, et al. Antihypertensive treatment and secondary prevention of cardiovascular disease events among persons without hypertension. Journal of the American Medical Association. 2011;305:913.
- Karanja N, et al. Acceptability of sodium-reduced research diets, including the dietary approaches to stop hypertension diet, among adults with prehypertension and stage 1 hypertension. Journal of the American Dietetic Association. 2007;107:1530.
- Maruthur NM, et al. Lifestyle interventions reduce coronary heart disease risk: Results from the PREMIER trial. Circulation. 2009;119:2026.
- Pimenta E, et al. Prehypertension: Epidemiology, consequences and treatment. Nature Review Nephrology. 2010;6:21.
- Dietary Guidelines for Americans, 2010. U.S. Department of Health and Human Services. http://www.cnpp.usda.gov/DGAs2010-PolicyDocument.htm. Accessed Aug.. 22, 2011.
- Rethinking drinking: Alcohol and your health. National Institute on Alcohol Abuse and Alcoholism. http://pubs.niaaa.nih.gov/publications/RethinkingDrinking/Rethinking_Drinking.pdf. Accessed Aug. 22, 2012.