What is High Blood Pressure?

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Arterial hypertension, typically known as high blood pressure or the “silent killer”, is an increasingly frequent disease which in itself does not cause any symptoms. However, if left unchecked it goes on to produce several complications in the brain, heart, large arteries and kidneys that can severely affect patients’ life expectancy and quality of life. High blood pressure is the most common risk factor associated with all cardiovascular diseases, which, in turn, represent the primary cause of death in Spain.

Blood pressure measurement has two components:

Heart contracting during systole

Systolic blood pressure. This is the maximum blood pressure value and corresponds to when the heart contracts (the systole phase). It is the pressure exerted against artery walls when blood is pumped out of the heart.

Heart contracting during diastole

Diastolic blood pressure. This corresponds to the minimum blood pressure value when the heart is between beats (the diastole phase). It refers to the blood vessels’ capacity to expand or contract depending on the volume and pressure of blood flowing through them (known as arterial distensibility), that is, the effect blood pressure exerts on vessel walls.

Types [Degrees] of hypertension

The European Society of Hypertension/European Society of Cardiology classifies normal blood pressure into three categories:

  • Optimal. When the systolic pressure is < 120 mmHg and the diastolic pressure is < 80 mmHg.
  • Normal. When systolic is in the range of 120–129 mmHg and/or the diastolic is measured to be 80–84 mmHg.
  • High normal. When systolic is in the range of 130–139 mmHg and/or the diastolic is 85–89 mmHg. 

Blood pressures greater than these values are defined as hypertension and classified into three grades:

  • Grade 1 hypertension. Systolic pressure of 140–159 mmHg and/or a diastolic value of 90–99 mmHg.
  • Grade 2 hypertension. Systolic pressure of 160–179 mmHg and/or a diastolic pressure of 100–109 mmHg.
  • Grade 3 hypertension. A systolic value of ≥ 180 mmHg and/or a diastolic pressure ≥ 110 mmHg.

Additionally, a classification known as isolated systolic hypertension exists when the systolic pressure is > 140 mmHg and the diastolic pressure is < 90 mmHg.

How many people does it affect?

High blood pressure is a very common disease throughout the world and affects one third of the Spanish population aged over 18. It affects over 20% of adults aged between 40 and 65 years and over 50% of those aged over 65. We know that its frequency increases with age. Lifestyle changes, such as a less healthy diet and a lack of exercise, have brought about an increase in the incidence of hypertension over the last few decades.                              

Substantiated information by:

Antonio Coca Payeras
Cristina Sierra Benito
Dolors Estrada Raventós
Miguel Camafort Babkowski
Mónica Doménech Feria-Carot
Rosa Soriano Giménez

Published: 20 February 2018
Updated: 20 February 2018


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