tel. (416) 591-1123What is Normal Blood Pressure?
By Dr. JJ Dugoua ND PhD
It is estimated that there are over 50 million people with high blood pressure, also known as hypertension, in the United States and approximately 1 billion worldwide.
Unknown Cause
Unfortunately, the cause of the most common type of hypertension, called primary or essential hypertension, is unknown; although genetics, lifestyle and diet are suspected. Hypertension can lead to a number of serious health concerns, including stroke, renal disease, heart attack, heart failure, heart pain (angina), eye disease (retinopathy) and many others.
Taking your Blood Pressure
Your blood pressure should be measured every time you visit your physician or licensed health care provider. Your physician will place a blood pressure cuff, known as a sphygmomanometer, around your arm, inflate the cuff and listen to your heart with a stethoscope. You may feel a slightly uncomfortable squeeze as the cuff is inflated. Blood pressure is measured in millimeters of mercury (mm of Hg). The first number corresponds to the systolic blood pressure (pressure during contraction of the heart) and the second number is the diastolic blood pressure (pressure during relaxation of the heart). For example, if your blood pressure was 130 over 85 (130/85 mm of Hg), your systolic blood pressure would be 130 and your diastolic pressure would be 85.
Normal Values
Based on clinical studies, the values that were once considered normal for systolic and diastolic blood pressure, 130/85, are too high.
In May 2003, the seventh report of the Joint National Committee (JNC) on the Prevention, Detection, Evaluation and Treatment of High Blood Pressure was published in the Journal of the American Medical Association. The purpose of the JNC is to evaluate clinical studies and, based on these, to issue guidelines for the prevention, detection, evaluation and treatment of high blood pressure. The JNC concluded that the risk of cardiovascular disease begins at a blood pressure above 115/75 mm of Hg, and not at 130/85 mm of Hg, as originally thought. The new classification of blood pressure for adults 18 years and older are as follows:
|
Blood pressure |
Systolic |
Diastolic |
Lifestyle changes |
Drug therapy |
|
Optimal |
115 |
75 |
Not required |
Not required |
|
Normal |
120 |
80 |
Encouraged |
Not required |
|
Pre-hypertension |
120-139 |
80-89 |
Yes |
Not required |
|
Stage 1 hypertension |
140-159 |
90-99 |
Yes |
Yes |
|
Stage 2 hypertension |
160 or above |
100 or above |
Yes |
Yes |
How your Doctor should take Blood Pressure
The JNC also established the proper procedure for taking an accurate blood pressure measurement. Please make sure your physician or licensed health care professional follows the steps below when taking your blood pressure.
1. The patient should be seated comfortably in a chair, not on the examining table, with their feet flat on the floor and their arm supported at heart level.
2. The patient should be seated for at least five minutes.
3. The appropriate blood pressure cuff size should be used (cuff must encircle at least 80% of the arm).
4. At least two measurements should be taken.
5. The blood pressure recorded is an average of the two measurements.
Lifestyle Changes
The JNC recommended a number of lifestyle modifications to effectively manage hypertension. These recommendations included weight loss, dietary sodium restriction, exercise, moderate alcohol consumption and a diet rich in fruits, vegetables and lowfat dairy products with reduced saturated and total fat.
References
Beers, M.H. and Berkow, R. 1999. The Merck Manual of Diagnosis and Therapy 17th Edition. Merck Reaseach Laboratories, Whitehouse Station, New Jersey. 2833 pages
Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr, Jones DW, Materson BJ, Oparil S, Wright JT Jr, Roccella EJ; National Heart, Lung, and Blood Institute Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure; National High Blood Pressure Education Program Coordinating Committee. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 2003 May 21;289(19):2560-72.