Conditions InDepth: Hypertension

Hypertension is the medical term for high blood pressure. Blood pressure is the measure of force that blood flow creates against the artery walls. High blood pressure is when this pressure is higher than expected.

Normal blood pressure is in the range of 120/80 millimeters of mercury (mmHg). The higher number, called the systolic, represents the pressure in the artery when the heart beats. The lower number, called the diastolic, represents the pressure when the heart is at rest. .

The American Heart Association (AHA) uses the following blood pressure categories:

  • Blood pressure is considered elevated, but not yet hypertension (abnormally high blood pressure) when the:
    • Systolic pressure is 120-129 mmHg and the
    • Diastolic pressure is 80 mmHg
  • Stage 1 hypertension:
    • Systolic pressure is 130-139 mmHg and/or
    • Diastolic pressure is 80-89 mmHg
  • Stage 2 hypertension:
    • Systolic pressure is greater than or equal to 140 mmHg and/or
    • Diastolic pressure is greater than or equal to 90 mmHg

There are 2 main types of hypertension:

  • Primary—hypertension without any known cause, most common cause
  • Secondary—hypertension with a known or underlying cause

The Cardiovascular System

The Cardiovascular System
Copyright © Nucleus Medical Media, Inc.

Causes

The blood vessels throughout the body are designed to help blood flow smoothly, direct blood flow where necessary, and help to manage blood pressure. High blood pressure may occur because of one or more of the following:

  • Damage to the walls of the blood vessels that make it difficult for blood to flow through
  • Build up of plaque (atherosclerosis) or blood clots on blood vessel walls that reduce the area the blood can pass through
  • Structural problems with blood vessels—from congenital conditions
  • Conditions or medication that make blood vessels tighten when they should not
  • Decreased elasticity of blood vessels—common effect of aging

These conditions make it harder for the heart to push blood throughout the body. The heart has to push harder for each heart beat and the blood flow can become more turbulent, which both increase pressure on the blood vessel walls.

Primary blood pressure often develops over time because of a combination of these factors.

Secondary hypertension on the other hand, usually develops more quickly and is caused by other health conditions, such as kidney or endocrine disorders, or sleep apnea. Over-the-counter and prescription medications can also cause secondary hypertension.

Next

References:

About high blood pressure. American Heart Association website. Available at:
...(Click grey area to select URL)
Updated July 12, 2016. Accessed September 20, 2016.
Hypertension. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115345/Hypertension. Updated August 29, 2016. Accessed September 20, 2016.
What is high blood pressure? National Heart, Lung, and Blood Institute website. Available at:
...(Click grey area to select URL)
Updated September 10, 2015. Accessed September 20, 2016.
Zieman SJ, Melenovsky V, Kass DA. Mechanisms, pathophysiology, and therapy of arterial stiffness. Arterioscler Thromb Vasc Biol. 2005;25(5):932-943.
12/11/2009 DynaMed Plus Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T115345/Hypertension: He J, Gu D, Chen J, et al. Premature deaths attributable to blood pressure in China: a prospective cohort study. Lancet. 2009;374(9703):1765-1772.
1/5/2018 DynaMed Plus Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T115345/Hypertension: Whelton PK, Carey RM, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2017 Nov 13. [Epub ahead of print].
Last reviewed January 2018 by EBSCO Medical Review Board Michael J. Fucci, DO
Last Updated: 2/8/2018

 

EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

To send comments or feedback to our Editorial Team regarding the content please email us at healthlibrarysupport@ebsco.com. Our Health Library Support team will respond to your email request within 2 business days.

advertisement