What is Hypertension or High Blood Pressure? An Explanation

Everyone knows what hypertension is. Many of your friends and relatives may be suffering from this chronic serious (although it does not seem serious because only a minor percentage of individuals suffering from high blood pressure have troublesome symptoms) disease. Hypertension (and its complications) is a silent killer and it is one of the leading causes of deaths worldwide.

What exactly is hypertension or high blood pressure?

Different experts explain/define blood pressure in different ways. Hypertension or high blood pressure is the high (more than normal) lateral pressure blood puts to the walls of the blood vessels, while flowing through it. It can be compared to water flowing through a rubber tube and if water puts excess pressure than the rubber tube can handle, there is a great risk of bursting of the rubber tube.

The same is true for blood vessels also, which are also elastic in nature and if excess pressure continues for long duration, aneurysms may develop, especially in smaller blood vessels of the brain and this is the reason brain stoke (most commonly due to bursting of aneurysms) is so common among individuals with high blood pressure.

From the above example it is not difficult to understand why and how hypertension develops. But the fact is we still do not know causes of most of the cases of hypertension, hence it is called essential hypertension. Practically more than 95% of cases are essential hypertension and very small percentage the cause is known.

Some of the causes of hypertension are:

  • Hypertension can develop if the walls of blood vessels become less elastic.
  • Hypertension can occur if there is excess blood volume for any reason.
  • Hypertension can develop if blood vessels constricts for any reason.
  • Hypertension can occur if osmotic pressure of blood increases, which puts excess lateral pressure to the blood vessel walls with same amount of blood in it.
  • Hypertension can occur if walls of blood vessels become thick, as seen in atherosclerosis (deposition of cholesterol in blood vessel walls).

Why the above mentioned things occur/happen is not clear and hence, we do not know the causes of hypertension.

Hypertension is classified as given below:

  • Normal blood pressure: systolic/diastolic: <120/<80 mm of Hg (mercury)
  • Pre-hypertension: systolic/diastolic: <120-139/<80-89 mm of Hg
  • Mild hypertension: systolic/diastolic: <140-159/<90-99 mm of Hg
  • Moderate hypertension: systolic/diastolic: <160-179/<100-109 mm of Hg
  • Severe hypertension: systolic/diastolic: <160-179/>110 mm of Hg
  • Isolated systolic hypertension: systolic/diastolic: >140/<90 mm of Hg

Image: markuso / FreeDigitalPhotos.net

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