Diagnosis of high blood pressure

Blood pressure is defined as the pressure exerted by the blood against the walls of the blood vessels, especially the arteries. Blood pressure that is higher than normal (see below for information on measurement and the normal range of values) is known as hypertension. Hypertension is a clinically important condition that requires management.1

There is no guarantee that a person with hypertension will present with any symptoms of the condition. About 30% of people actually do not know that they have high blood pressure, and this ignorance can last for years.1 For this reason, it is advisable to undergo periodic blood pressure screenings.2

High blood pressure should be treated and controlled by lifestyle changes, medication, or a combination of both.1,2

Definition

Blood pressure is the force with which blood, moving around the body, pushes against blood vessel walls.

Hypertension is defined as a level at or above 140/90 mmHg – individuals with these blood pressure values benefit from antihypertensive treatment. “Optimal” blood pressure is defined as being less than 120/80 mmHg.1

Category Systolic   Diastolic
Optimal <120 and <80
Normal 120–129 and/or 80–84
High normal 130–139 and/or 85–89
Grade 1 hypertension 140–159 and/or 90–99
Grade 2 hypertension 160–179 and/or 100–109
Grade 3 hypertension ≥180 and/or ≥110

Williams B et al. European Heart Journal (2018) 39, 3021–3104

Measurement

Blood pressure is measured in millimetres of mercury (mmHg) – it is the force with which the mercury is physically moved. A blood pressure reading is shown as two numbers, for example, 140/90 or 160/110.

The first number measures the pressure against the walls of your blood vessels when the heart is pumping blood to your organs (systolic blood pressure). The second number measures the pressure against the walls of your blood vessels when the heart is between beats and resting (diastolic blood pressure).

It is normal for your blood pressure to vary. It varies with the time of day or night. It can even vary slightly with each heartbeat. Normally, it increases during activity or excitement, and decreases at rest. Therefore, it is important to have your blood pressure taken under proper conditions and on more than one occasion.

References

1. Kaplan NM. Clinical Hypertension, 9ed. Lippincott, Williams & Wilkins; 2006.
2. Mancia G, et al. Eur Heart J. 2013 Jul;34(28):2159-219.